
Class Jl^AdJLi?. 
Boole . L. ?: 



COPYRIGHT DEPOSm 



^he Ransome Boot^ 



HOW TO MAKE AND 

HOW TO USE 

CONCRETE 



M 

CAMPBELL 



Illlllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllli 



The Ran^ome Book \ 

HOW TO MAKE AND '^rii'm, 

HOW TO USE I 

CONCRETE I 



Written and Compiled by 

H. COLIN CAMPBELL, C.E., E.M. 



PRICE ONE DOLLAR 



" Well-Mixed Concrete for Permanence.' 



Ransome Concrete Machinery Co. 

The Pioneer Builders of Concrete Machinery 

115 BROADWAY NEW YORK CITY 

FACTORIES 

DUNELLEN, N. J. READING, PA. OSHKOSH, WIS. 



N!l!l||||||l!{||||{|||||l|lilllllllll!lllllllllllllll 



•^\ 



A^'^^„.^ 



Copyrighted, 1918, by 
Ransome Concrete Machinery Co. 



^'JG -2 19/8 

©CI.A499995 
<i. r \ 



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INTRODUCTION 

In issuing this booklet the Ransome Concrete 
Machinery Company is making a departure from 
. usual practice that it is hoped will be popular. The 
Ransome line of machinery and concreting equip- 
ment has been subordinated to those fundamental 
practices which govern success in the use of concrete. 
The thought is this: However good the machine 
may be, thp concrete cannot be all that it should be 
unless the human element can be controlled. The 
machine cannot do that. This is up to the man on 
the job. Success in the use of concrete, as in the use 
of any other building material, lies in following well- 
established rules that have proved themselves the 
proper guide. 

Concrete is too big a subject to be covered within 
the limited space of this booklet; but there have 
been gathered here useful data that are applicable to 
almost any and every kind of concrete work. Every 
page, it is believed, contains more than one reminder 
of the things that should be done but which are 
frequently overlooked or neglected. 

Among many sources of information on the uses 
of concrete are the numerous booklets and pamphlets 
issued by the Portland Cement Association. All of 
these publications can be obtained for the asking, 



iv INTRODUCTION 

and a collection of them forms a valuable reference 
library on good concrete practice and the many 
popular uses of concrete. It is suggested that users 
of Ransome equipment will find much profitable 
information in the following, copies of which may 
be had free of charge by addressing the Portland 
Cement Association, 111 West Washington Street, 
Chicago : 

Concrete Silos 

Portland Cement Stucco 

Concrete in the Country 

Farmers' Handbook on Concrete Construction 

Concrete Swimming and Wading Pools 

Concrete Linings for Irrigation Canals 

That Alley of Yours 

Concrete Houses and Why to Build Them 

Fundamentals of Reinforced Concrete Design 

How to Maintain Concrete Roads and Streets 

Recommended Specifications for Reinforced Concrete Design 

Suggested Specifications for Concrete Floors 

Why Build Fireproof? 

Integral Curb for Concrete Pavement 

Cement Stave Silos 

Concrete Tile for Land Drainage 

Protecting Concrete in Warm Weather 

Concrete Grain Bins and Elevators 

Bulk Cement 

Concrete Ships 

Facts Every One Should Know about Concrete Roads 

Standard Specifications and Tests for Portland Cement 

Specifications for Concrete Roads, Streets, and Alleys and Paving 

between Street Car Tracks. 
Concreting in Cold Weather 
Tennis Every Day on Concrete Courts 
Concrete Septic Tanks 
Concrete Fence Posts 
Small Concrete Garages 



INTRODUCTION v 

Concrete Facts about Concrete Roads 

Concrete Feeding Floors, Barnyard Pavements and Concrete Walks 

Proportioning Concrete Mixtures and Mixing and Placing Concrete 

Concrete Foundations 

Concrete Troughs, Tanks, Hog Wallows, Manure Pits, and Cisterns 

Concrete Sewers 

This booklet falls short of what we want it to be. 
It could be made better if we had the suggestions of 
our many friends. We therefore invite suggestions 
and criticism as to how it may be made of greater 
value to you, so that in future editions we can 
endeavor to more nearly approach what is impossible 
to attain — perfection. 



CONCRETE 

HOW TO MAKE AND USE IT 



GENERAL 

Many persons are under the impression that 
Portland cement is the material most responsible for 
the success of concrete work. While it is true that a 
standard Portland cement should be used, it is 
nevertheless equally as important, and in some 
cases more important, that great care be taken in 
selecting and proportioning the aggregates, — that is, 
the sand and pebbles or broken stone which form the 
main bulk of concrete. Portland cement is manu- 
factured after methods so exact that quality can be 
absolutely controlled. Any one should be able to 
realize the truth of this statement, because if Port- 
land cement manufacturers did not make a product 
up to specification requirements they would soon be 
without a business. 

All standard Portland cements when they leave 
the mill are of high quality. The only thing that 
can happen to them to render them worthless is 
improper care in storage. Portland cement is 
sensitive to water. If it were not it would not per- 
form the function intended of it, — that is, bind the 
particles of sand and pebbles or broken stone 
together into what eventually becomes stone. 
1 



2 THE RAN SOME BOOK — HOW TO 

STORAGE REQUIREMENTS 

Portland cement should never be piled on the 
ground out on the job, nor in any shed where it can 
absorb dampness. Only little moisture is necessary 
to spoil the cement. It will partly if not completely 
harden, due to this moisture, and that will make it 
unfit for use in a concrete mixture. Out on the job 
cement should be piled on boards and otherwise pro- 
tected against sudden showers. On the average job 
only so much cement should be piled out of doors 
near the work as can be used within a definite period 
of hours or the working day. Any other quantity 
that may be necessary to keep near the job should 
be kept in a tight shed that will thoroughly protect 
it from moisture. 

AGGREGATES 

Many users of concrete think that bank-run 
gravel, meaning the natural mixture of sand or 
gravel with more or less foreign material as it comes 
from the gravel pit, is a suitable material for use in 
concrete. Concrete failures have resulted from 
using such unscreened material. It is not suitable 
for several reasons: It often contains more or less 
loam, clay, or similar foreign material. Sometimes 
the bank or deposit when opened for use is not 
stripped of the overlying soil, and as material is 
dug out of the face of the pit this soil falls down and 
becomes mixed with the bank material. Often the 
deposit contains clay or silt due to the manner in 
which the deposit was originally formed in nature. 

No concrete can be stronger than the materials of 



MAKE AND HOW TO USE CONCRETE 3 

which it is composed, and foreign material, like clay, 
loam, or silt, prevents the cement from coming in 
contact with the surfaces of the sand and pebble 
particles, thus they cannot be bonded together. In 
other words, such foreign material acts to adulterate 
the cement. Often, also, these foreign materials have 
some free chemical in them which acts injuriously 
upon the cement and prevents it from hardening. 

Bank-run gravel usually contains twice as much 
fine material as coarse, while in the average concrete 
mixture these proportions should be about the 
reverse. The natural run of bank gravel contains 
about forty-five per cent of voids or air spaces. In 
order to fill these and make a dense concrete, the 
amount of sand should be about half the volume of 
pebbles. If more sand than this is used, as would 
be the case when the bank-run material is employed 
exactly as coming from the pit, it is necessary to use 
a much greater quantity of cement to fill up these 
voids or air spaces so as to give the concrete the 
desired strength. This, of course, is an uneconomical 
use of cement. The amount of cement used in an 
ideal mixture, as, for example, one sack of Portland 
cement, two cubic feet of sand and four cubic feet of 
pebbles or broken stone, is sufficient, when all have 
been thoroughly mixed with the proper amount of 
water, to coat every particle of sand, thus forming a 
sand-cement mortar which will practically fill all 
voids in the pebbles or broken stone, while voids 
in the sand are filled by the cement. If, however, 
these proportions are reversed by using twice as 



4 THE RANSOM E BOOK — HOW TO 

much sand as pebbles, the cement is naturally in- 
sufficient to coat the increased number of sand grains, 
not to mention fill the voids or air spaces in their 
volume. The result is a weak and porous concrete. 

Mere inspection of a gravel bank will not tell any 
one whether the sand and pebbles are in correct pro- 
portions. As a matter of fact they hardly ever are. 
It is also true that no two loads of bank-run gravel 
are uniform in relative proportions of fine and 
coarse material, consequently the concrete made 
from such material is not uniform. By looking at 
an ordinary gravel bank one can see how in working 
or digging from the deposit the pebbles drift down 
the face, as it were, and become separated from the 
sand. 

SCREEN BANK -RUN MATERIAL 

To make good concrete, bank-run materials must 
be screened by separating them into at least two 
grades of material. The finer material, which is in 
the sand, is arbitrarily defined as that which will 
pass through a screen having four meshes to the 
linear inch. The coarser material, called pebbles, is 
that retained on such a screen and ranging in size 
from 34 i^ch upward to particles as large as can 
conveniently be used on the job in question. The 
larger sizes will vary from % inch for fence posts 
and other concrete products up to 1, 13^ and IJ^, or 
perhaps even 3 inches for work ranging from rein- 
forced concrete floors and walls to heavy and massive 
foundations, where the 3 inch particles may be used 
if the volume of them is not in excess. 



MAKE AND HOW TO USE CONCRETE 5 

SCREENING PAYS 

Many persons do not believe it is worth the 
trouble to separate bank-run material, and when 
specifications call for a 1:2:4 mixture they think 
that one volume of cement, or one sack of cement, 
to 6 cubic feet of the natural bank-run material is 
just the same thing. In a 1:2:4 mixture the 2 cubic 
feet of sand goes to fill the voids or air spaces in the 
4 cubic feet of pebbles, so that one sack of cement, 
2 cubic feet of sand, and 4 cubic feet of pebbles or 
broken stone properly mixed make about 4.5 cubic 
feet of concrete in place. On the other hand, 6 
cubic feet of the natural bank-run material with, one 
sack of cement will make little if any more than 
6 cubic feet of compacted concrete. As between 
the 1:2:4 mixture and the 1:6 mixture the latter is 
about one third greater in volume, yet has no more 
cement in it than the other mixture, consequently 
cannot be so strong, cannot be dense, and hence 
cannot be water-tight. More often than otherwise 
a disregard of the essentials just stated is what pro- 
duces the leaky concrete of which we frequently 
hear. It is true economy to screen bank-run material 
and reproportion the sand and pebbles in definitely 
measured volumes. 

WASHING AGGREGATES 

If aggregates contain more than a certain per 
cent of sand, loam, silt, or other foreign material, 
they should be washed before used in a concrete 
mixture. Specifications for concrete work some- 



6 THE RAN SOME BOOK — HOW TO 

times vary in stating the amount of such foreign 
material that may be left in the aggregates. This 
does not mean that it is at all desirable that such 
material should be there, but it is generally believed 
that from three to five per cent will not, in most 
classes of concrete work, affect the final strength. 

A number of methods can be employed to wash 
aggregates when necessary to do so. Washing 
troughs can easily be devised and such troughs can 
be made to combine the features both of washer and 
screen. A suggestion for such a washing device is 
shown in an accompanying sketch. 



.ffaf//^ -^fffarar 







A simple washing trough with screen at the lower end, by means of which dirty bank- 
run material can easily be washed free from clay or other foreign material and the sand 
separated from the pebbles. The platform on which the sand and pebbles are dis- 
charged should be sloped slightly to cause the wash water to flow away freely. 



MAKE AND HOW TO USE CONCRETE 




THE RAN SOME BOOK -- HOW TO 




MAKE AND HOW TO USE CONCRETE 



Symbol 


Pescrlpfion 


/\ 


Use, 2 - %" - II '/z" bolts ^ii-h tA^ashers 







c 


II 1 ^ II — f-jii II II ,1 


£y 


II p - II — /^ii II II II 


£• 


JI ^ . II ^ S'/Z" II n 


F 


" no//s II '1 II 


G 


2 - ^/G" ~ t3'/z" n II n 


H 




Jt 


Z '■ l5'/2" 


J 


"4. " ~ /J^" 


K 


/ -^A* 17 '/z" 


L 


"2 >i ~ t5'/z" 


M 


B/n G^fes /B*^ A/6" Opening - Steel 


N 


steel Chutes 


R 


^ood Hopper- Steel Lineal 


Note:- Obfcfin sfcfndarcf sprockets etc. ne<3rfo the foUoi^Jn^ 
sizes: - 


5-1 


5procket - PP. 9.72' T- II 1 Roller choin, pitch ^2.61" 


5-2 


" >^ ZZSe' " ^28 l6~6yoiyreg'c(. 


5-J 


H II 5>/2" " ^1/ J^ 


Same pif-ch 


5-4 


" 1' ja46'' 1, =je 


14-92 long 


5-5 ' 


7.85" 1,-9 ' 


Samepitch 


5-e 


,1 i< 2455" 1.-29 


^ IS'- y long 


5-7 


5pur0ear " JQ 65" "^76 ' Face J" 


5-8 


Pinion" "6.01" „ 15 " 3" 


P 


Pul/ey- 8" ^30" requires 6" sg/e. lecTfher be/f 


B.G-1 


Bevel Gear FD.3I44 7-= 79 pitch iy4" bore 27/6" 


B.6.2. 


" 799 T-20 " '^ ^ 1%" 


5C'60 


Gilbert Screen ^0" inner ^veQrlng skirt 


5c'-54 


„ „ S4" No we^rinq skirt 



10 



THE RAN SOME BOOK — HOW TO 



BILL OF MATERIAL 

FOR 

SEMIPORTABLE GRAVEL PLANT 

MACHINERY 

1 32'-0" Incl. Bucket Elevator — 50 tons per hour 

1 60" Gilbert Screen, with inner skirt 

1 54" Gilbert Screen, no inner skirt 

1 22'-2 1^" turned shaft (approx. length) 

6 fixed post bearings 

1 3'-6"xl H" dia. countershaft (approx. length) 

1 4'-0" X 2 1^" dia. countershaft (approx. length) 

6 sprockets, 1 spur gear and pinion (see Table) 

70'-0" S.B.R. 2.61" pitch drive chain (approx.) 

1 pulley 8" face, 30" dia. 

2 steel screen chutes 

1 wood steel-lined head hopper chute 

1 wood steel-lined team hopper 

1 8 H.P. gasoUne engine 

1 centrifugal pump (cap. 300 gals, per minute, diach. pipe 4" dia.) and necessary 

pipe 
I 10 H.P. gasoline engine for pump 
4 bin gates — St'd Quadrant, 12" x 16" 
1 grizzly screen, \%" Q openings (4'-8" x 5'-4") 



\'o. Pes. 


Dimensions 


Material 


Bd. Ft. 




Si 


ubframes 






18 


2" x 6" X lO'-O" 




Y. P. 


180 


9 


8" X 8" X 4'-2" 




Y. P. 


203 


6 


8" X 8" X 4'-6" 




Y. P. 


144 


2 


8" X 8" X 9'-0" 




Y. P. 


96 


3 


8" X 12" X 9'-0" 




Y. P. 


216 


5 


8" X 12" X lO'-O" 




Y. P. 


400 


60 


14" X 6" dowels 




Steel 




4 lbs. 


20d. nails 








12 


%"x 13" bolts and 


washers 






16 


5^" X IIH" bolts and washers 






Floor 




BINS 






6 


2" X 4" X 16'-0" 




Y. P. 


64 


2 


2" X 4" X 12'-0" 




Y. P. 


16 


5 


1" X 2" X 14'-0" 




Y. P. 


12 


2 


2"xlO"x9'-0" 




Y. P. 


30 


18 


2" X 12" X lO'-O" 




Y. P. 


360 


10 


2" X 12" X 18'-0" 




Y. P. 


360 


11 lbs. 


lOd. nails 










Side W 


ALLS — Gray 


EL 




16 


2" X 4" X 7'-10" 




Y. P. 


83 


20 


2" X 10" X 12'-0" 




Y. P. 


400 


9 lbs. 


lOd. nails 










Partition and End Wall 


— Gravel 




14 


2" X 4" X 7'-4" 




Y. P. 


74 


16 


2" X 12" X 12'-0" 




Y. P. 


384 


7 lbs. 


lOd. nails 










End and 


Side Walls - 


— Sand 




8 


2" X 4" X 7'-4" 




Y. P. 


39 


8 


2" X 12" X lO'-O" 




Y. P. 


160 


14 


2" X 4" X 7'-10" 




Y. P. 


74 


20 


2" X 10" X lO'-O" 




Y. P. 


333 


111/2 lbs. 


lOd. nails 
















Carried forward 


3.62S 



MAKE AND HOW TO USE CONCRETE 



11 



BILL OF MATERIAL 

FOR 

SEMIPORTABLE GRAVEL PLANT 





GiHTS AXD Posts 


Brought forward 




No. Pes. 


Z)imensi07is 




Material 


Bd.F 


7 


4" X 4" X lO'-O" 




Y. P. 


93 


6 


6" X 6" X lO'-O" 




Y. P. 


180 


4 


6" X 6" X 20'-0" 




Y. P. 


240 


4 


8" X 8" X 14'-0" 




Y. P. 


300 


2 


8" X 8" X 20'-0" 




Y.P. 


214 


4 


8" X 8" X 12'-0" 




Y.P 


256 


46 


5^" X 9 J^" bolt? and ^ 


iv-ashers 






68 


5^" X 11" bolts and w 


ashera 






116 


^" X 13H" bolts and 


washers 






48 


Vs" X loM" bolts and 


washers 






16 


3" X 4" X ^" plate 








2 


1" dia. steel rod — lO'-O" 






4 


1" dia. steel rod — 11' 


-2" 






2 


1" dia. steel rod— 10' 
Top 


-7" 
Frame 






2 


2" X 4" X 3'-4" 




Y.P. 


4 


1 


2" X 6" X 12'-0" 




Y. P. 


12 


2 


2" X 6" X 14'-0" 




Y. P. 


28 


3 


2" X 8" X 12'-0" 




Y.P. 


48 


4 


4" X 6" X 9'-0" 




Y.P. 


72 


2 


4" X 6" X l'-9" 




Y.P. 


7 


6 


6" X 6" X 8'-0" 




Y.P. 


144 


4 


6" X 6" X 9'-0" 




Y.P. 


108 


1 


6" X 8" X 14'-0" 




Y.P. 


56 


1 


6" X 12" X 13'-0" 




Y.P. 


78 


2 


S" X 10" X 9'-0" 




Y. P. 


120 



^" Bolts and Washers 
12 6H"; 4 llj^"; 28 13"; 24 133^"; 
4 15H"; 2 M" X 24" 





Settling 


Tank 






6 


2" X 4" X lO'-O" 




Y. P. 


42 


2 


4" X 4" X 8'-0" 




Y.P. 


21 


2 


6" X 6" X 9'-0" 




Y. P. 


54 


4 


6" X 8" X 9'-0" 




Y. P. 


144 


.0 


2" X 12" X 14'-0" 




Y.P. 


280 


1 


2" X 12" X 16'-0" 




Y. P. 


32 


lib. 


lOd. nails 









Bolts and Washers 
6 3^"x8"; 6 3^"xl0"; 8 ?^"xl5M"; 
8 M"xl5^"; 4 Mxl7M" 





Team 


Hopper 








4"xS"x 11 '-0" 
8" X 8" X 2'-0" 
8" X 8" X 7'-0" 
8"x8"xll'-0" 
2" X 8" X 12'-0" 
20d. nails 






Y. 
Y. 
Y. 
Y. 
Y. 


P. 
P. 
P. 
P. 
P. 


60 
43 
149 
118 
144 



6,675 



12 



THE RAN SOME BOOK — HOW TO 



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"1 s^^^^ ' '^"-1 


l'.^^^^'*^ Jl[ 




\j "co Ji 5>>^ ■$ §-"*^ >, 5 5 ^ 5; -§ j; ;■ |. i' ^ v;, «;; 
'is ^ § h |-"l ^^ ^'^ « ^^^''©•S ^* S-'o'i 







MAKE AND HOW TO USE CONCRETE 13 

DESIGN FOR WASHING PLANT 

Accompanying drawings suggest details for a 
semiportable gravel-screening and washing plant. 
This has been designed with a view to producing 350 
cubic yards of washed aggregates per day. An 
accompanying table gives a bill of lumber and a list 
of machinery estimated as necessary to build and 
operate this plant. Horsepower required will vary 
considerably, depending upon the design and capa- 
city of the plant. Gasoline motive power is very 
convenient, economical, and adaptable. The partic- 
ular advantages of the plant shown in this design 
are that preparation of sand and pebbles for use in 
concrete can be effectively done anywhere that neces- 
sity compels the use of a deposit that can be made 
suitable if the materials are washed and screened. 

The quantity of water required to thoroughly wash 
and size sand and pebbles in a mechanical plant of 
this kind varies from one half to one gallon per 
minute per cubic yard of material prepared per day. 
That is, if the capacity of the plant is 500 yards of 
prepared material per day, water required Der minute 
will vary from 250 to 500 gallons. Such wide range 
is due to variations in the amount and nature of the 
matter to be washed out. The general operation of 
preparing sand and pebbles for use as aggregate in 
concrete consists first of excavating the material 
from the bank or elevating it from the beds of 
streams, transporting it to the washing plant, 
where it is elevated to the hopper located directly 
above suitable screens, dumping it into these screens 



14 THE RANSOME BOOK — HOW TO 

and playing upon the material water under pressure, 
which in connection with the agitation in the screens 
causes rolling and tumbling of materials and frees 
them of foreign matter. 

Screens used in the commercial preparation of 
aggregates can be classified as gravity, reciprocating, 
and rotary. Experience has generally proven that 
gravity screening plants are not in all cases as 
satisfactory as other types in securing a product 
possessing all desirable qualities. This is due largely 
to the great variety of material found in different 
pits and often in different parts of the same pit. 
Reciprocating or vibrating screens generally give 
better results. Cylindrical screens are made by 
attaching perforated sheet metal or wire cloth to 
circular frames, the size of perforations being 
governed by the grading of output desired. To 
obtain material properly sized for some concrete 
construction involves coarse aggregate from 34 to 
13/^ inch and washed sand from 34 inch to that which 
will be retained on a No. 100 mesh screen. Perfora- 
tions are in most cases 13^ inch round holes in the 
first conical screen, and % inch diameter in the 
next screen. Material from the last screen should 
then be discharged into a settling tank. Wherever a 
grading of material is required which lies between 
34 and 3^ inch or 34 ^^^ 1 inch the material must 
pass through a screen with 1 inch or 3^ inch perfora- 
tions and be retained on a screen having -^ inch 
perforations. It should be remembered that unless 
a very large percentage of the material ranges from 



MAKE AND HOW TO USE CONCRETE 15 

}4 to 3^2 iiich or from 34 to 1 inch, as it comes from 
the pit, the foregoing grading cannot be secured in 
the same operation that produces the coarse aggre- 
gate ranging from M to 13^ inch. When specifica- 
tions refer to material retained on a 34 iiich wire 
mesh over a circular frame of suitable diameter. 
Testing-screens of this kind are held in a horizontal 
position when the material is screened through them, 
the screen being shaken by hand enough to cause 
the material under 34 iiich to pass through the 
openings; therefore the perforations or openings in 
screens used when washing or screening materials 
on a large scale must be of such diameter as will 
produce materials conforming to those obtained by 
the hand-screen test. 

It will readily be seen that sand and some large 
aggregate can be made to pass over instead of 
through a 3^ inch mesh screen if the angle at which 
it is set and the speed of travel are made slow enough. 
Many materials have been used as aggregates in 
concrete construction. Various kinds of stone 
screenings are used at times in place of sand. In 
such cases the screenings should have the same 
sizing as would apply to natural sand. 

The particles which may be considered as dust 
should be removed by washing or otherwise. A 
particular trouble sometimes encountered with stone 
screenings, especially from certain kinds of lime- 
stone, is that the particles themselves are coated 
with a very fine dust or powder which prevents the 
cement from coming in contact with them and 



16 THE RAN SOME BOOK — HOW TO 

sometimes causes considerable ^'balling up" of the 
mass in the mixer. The same holds true of some 
kinds of coarse limestone aggregates. If this trouble 
is encountered the aggregates should be washed. 



GRADING OF AGGREGATES 

Aggregates should be well graded. The re£.son for 
this can be illustrated in a simple way. If we draw 
a number of circles, say, one inch in diameter, touch- 
ing one another, it will be seen that there are spaces 
among and between them in which smaller circles 
may be drawn. After these smaller circles have been 
drawn touching the larger ones, there still will be 
spaces in which still smaller circles may be drawn. 
These circles and the spaces correspond to the 
pebbles and the voids or air spaces in their bulk. It 
is necessary, therefore, that the larger particles pre- 
dominate and that the grading of the materials be 
such with respect to the quantity of smaller particles 
contained in the bulk as to reduce these voids or 
air spaces to the lowest percentage. After they have 
been so reduced by the best grading possible, the 
sand voids or air spaces are filled by using the proper 
amount of cement. 

Various tests may be made to determine the quan- 
tity or volume of voids or air spaces contained in 
any bulk of material. For great precision rather 
elaborate tests are necessary. Fairly accurate deter- 
minations may be made as follows: 



MAKE AND HOW TO USE CONCRETE 17 

FIRST METHOD 

Weigh the vessel and then fill level full with water, 
then weigh again. Call the net weight of the water 
C. Say, for example, it proves to be 80 pounds. 
Remove the water, dry and fill the vessel level full 
with the aggregate. Weigh and call the net weight 
of the aggregate B. Say this is found to be 120 
pounds. Then pour water slowly into the aggregate 
until the vessel is again level full of water. Weigh 
and call the net weight of the water and aggregate A. 
Say it is 160 pounds. Then the percentage of voids 
is 100 times the quantity ^^^, or in this particular 
case 100 times '-^^, = 100 times f^ = ^-^ = 4000 
^ 80 = 50, or 50% of voids. 

In introducing the water into the vessel containing 
the aggregate care must be taken to prevent en- 
trapping air. It is good practice, therefore, to apply 
the w^ater all at one point along the side of the vessel. 
In determining the voids in sand or fine gravel the 
method of procedure outlined above, which answers 
for coarse aggregate, should be slightly modified. 
After determining the net weight of the water (C) 
and the net weight of the sand (B), instead of pouring 
water into the sand, the sand should be removed, the 
vessel filled about half full of water, and the sand 
poured into the water. The object of pouring the 
sand into the water is to expel the air, which is im- 
possible if .the order is reversed. As most sands have 
less than fifty per cent voids the water will overflow 
the vessel before it is level full of sand. When this 
point is reached care should be taken to keep the loss 



18 THE RAN SOME BOOK — HOW TO 

of fine particles down to a minimum. When the 
vessel is level full of sand and water and all the 
overflow of water carefully wiped off, the net weight 
of the sand and water is obtained and the voids 
determined as above, from the equation, per cent of 
voids = 100 times ^\ 

SECOND METHOD 

Procure two similar vessels wdth flat bottoms and. 
vertical sides. Fill one level full with water and the 
other with the aggregate. Dip water from the 
vessel of water into the other until it appears on the 
surface, being careful not to spill any water. Measure 
the distance between the top of the vessel and the 
surface of the water. This distance divided by the 
total depth of the vessel and multiplied by 100 gives 
the per cent of voids in the aggregate. Say we have 
a vessel 18 inches deep and after the above operation 
the surface of the water is six inches below the top of 
the vessel. This would indicate a per cent of voids of 
1^ times 100 = ^= 33i%. 

Proceed exactly as above when working with a 
coarse aggregate, but with sand start with one of the 
vessels empty and the other full of water. Dip a 
little less than one third of the water from the full 
vessel into the empty one and then pour the sand 
into the vessel containing the smallest amount of 
water until it is level full of sand. If the. sand has 
more than one third voids, more water will have to 
be added; if less than one third voids it might be 
necessary to dip some of the water back into the 



MAKE AND HOW TO USE CONCRETE 19 

other vessel. With this method care must be taken 
that no water is lost; always dip water from one 
vessel into the other, so that at the end all the water 
started with is in the two vessels. Measure and 
figure for voids exactly as above. 

THIRD METHOD 

Carefullj^ measure the capacity of the vessel. Say, 
for example, it takes ninety small measures of water 
to fill the vessel level full. Empty out the water, fill 
the vessel with the aggregate, and then note how 
many small measures of water can be poured into 
the aggregate until the vessel is again level full of 
water. Suppose it requires thirty small measures to 
do this — then the per cent of voids is equal to one 
hundred times the result obtained by dividing the 
number of small measures of water added to the 
aggregate by the number of small measures of water 
required to fill the vessel; or, in this case 100 times 

30 ^ 3000 ^ 33i% voids. 

When using this method to determine the voids in 
sand or fine aggregate first place a given number of 
sm.all measures of water in the vessel, saj^ a few less 
than one third the number required to fill the ves- 
sel, then pour the sand slowly into the water. If 
you are able to fill the vessel with sand without 
bringing water to the surface add enough measures 
of water to do this; or if on the other hand you have 
started with too much water, dip out enough so that 
the vessel may be filled with sand without causing 
the water to overflow. Note how many measures of 



20 THE RAN SOME BOOK — HOW TO 

water you started with and how many were added 
or dipped out and obtain the per cent of voids as 
pointed out. 

FOURTH METHOD 

The following method of determining voids applies 
to sand only and is probably the best. Fill the vessel 
with sand and let the net weight of sand equal B. 
Fill the same vessel with water and let the net 
weight of the water equal A. Then the per cent of 
voids equals 100 ^Yx'a'es"^ equal 100 times |^. 

Of the above methods for determining voids in 
coarse aggregate^ the first is the most accurate, but 
approximate results may be obtained with the others, 
the value of the determination depending upon the 
care with which the work is done. At least three 
determinations for voids should be made and the 
result averaged. 

When deciding upon a mixture bear in mind that a 
first-class concrete requires that the cement be a 
little more than sufficient to fill the voids in the sand 
and that the cement and sand mortar must a little 
more than fill the voids in the gravel or stone. This 
means that if the sand at hand contains thirty-three 
per cent of voids, one cubic foot of cement (one sack, 
ninety-four pounds) can be mixed with two and one 
half cubic feet of sand, and if the gravel or stone has 
forty-five per cent of voids, the mixture of one sack 
of cement and two and one half cubic feet of sand 
can be mixed with four cubic feet of gravel or stone. 
Such a mixture will make a good concrete, but if an 



MAKE AND HOW TO USE CONCRETE 21 

exceptionally strong, dense concrete is desired, the 
mixture — with the aggregates referred to — should 
be one sack of cement to two cubic feet of sand and 
three cubic feet of pebbles or stone. 

MISCELLANEOUS AGGREGATES 

Various kinds of stone or rock and substitutes for 
them are used in concrete work. Different authori- 
ties have given slightly varying opinions as to the 
order of preference in which certain materials used 
as aggregates stand. The following table gives the 
principal kinds that have been considered, in the 
order in which they are generally valued : 

Trap Rock 100 

Granite 90 

Quartz Gravel 90 

Hard Limestone 80 

Soft Limestone 75 

Slag 75 

Slate 60 

Shale 55 

Cinder 50 

Just why slate and shale should be considered it is 
hard to say, since both of these materials are of a 
form that makes them particularly unsuited for use 
as concrete aggregate. The particles are flat and 
elongated, and regardless of how well mixed with the 
sand- cement mortar of a concrete mixture, cannot 
be made to produce a dense concrete. Late tests 



22 THE RAN SOME BOOK — HOW TO 

seem to show that slag stands higher up in the hst 
than credited in the above table. Slag in this case 
means slag from blast furnace operations in smelting 
iron ore. Nearly all other slags are unsuited for use 
as concrete aggregate because of the excessive 
quantity of free chemicals they contain and the 
injurious effect these will have upon the cement. 

FIRE RESISTANCE OF AGGREGATES 

Another thing should be borne in mind in con- 
nection with aggregates. Concrete is a great fire- 
resisting material, partly because the cement itself 
m process of manufacture has been subjected to very 
high heat. However, the cement alone will not safe- 
guard the concrete if the aggregates of which it is 
composed are not in themselves of a fire-resisting 
nature. Trap rock and slag, from the very nature of 
their origin, have been subjected to high heat, and 
are therefore good fire-resisting aggregates. Some 
gravels have good fire-resisting qualities. 

Granite, though hard, may easily be affected by 
intense heat because it tends to burst or crack. Some 
limestones are soft and become converted into lime, 
which, as every one knows, is made by burning lim.e- 
stone. Trap rock is regarded as one of the ideal 
aggregates. It is hard, and breaks into shapes that 
make a dense concrete. 

For roads and pavements which from the nature of 
their use are subjected to heavy traffic and impact, 
the aggregates should be tough and wear resisting. 

Cinders are used to some extent in concrete work 



MAKE AND HOW TO USE CONCRETE 23 

where lightness rather than strength is required, as 
in some reinforced concrete floors. Cinders, how- 
ever, make a porous concrete. Whenever used they 
should be free from ash and particles of unburned 
coal. 

SIZE OF AGGREGATES 

The maximum size of coarse aggregate is deter- 
mined by the thickness of the section in which used. 
Aggregate particles should always be less than half 
the thickness of the wall or section being placed. A 
maximum of one third such dimension is probably 
best. In some cases this maximum cannot be used, 
because the reinforcing that must be embedded in 
the concrete and the position of such reinforcing pre- 
vent the use of such large particles. It is difficult to 
cause concrete containing too large particles of 
aggregate to settle well around reinforcing and 
everywhere adhere or bond to it. 



MIXING WATER 

A very good rule to observe in connection with 
water used for mixing concrete is that it be equal in 
quality to drinking water. It should be clean, free 
from vegetable and animal matter, and should not 
contain acid or alkali. If water containing alkali is 
used, the result is usually a formation on the concrete 
of a whitish deposit called efflorescence. If alkali is 
present in excessive quantities it may affect the final 
strength of the concrete. 



24 THE RAN SOME BOOK — HOW TO 

PROPORTIONING CONCRETE MIXTURES 
USUAL METHODS 

For very accurate work concrete is proportioned 
after determinations have been made in a laboratory 
or otherwise to ascertain the exact quantities of each 
ingredient which should be used, or which is neces- 
sary to make the mixture as dense and strong as 
possible, that is, as free from voids or air spaces. On 
much work such exact methods are not followed. 
Proportioning is ordinarily done by volume. One of 
the commonest mixtures used is the 1:2:4 mixture, 
which is largely employed for most reinforced con- 
crete work. Some modification of proportions is 
necessary, depending upon the kind of work and the 
grading of the materials used. For example, if there 
is lack of uniformity in grading of the sand or pebbles, 
or both, and the work must be water-tight, then a 
1:2:3 mixture is much safer than a 1 : 2 : 4. A table of 
mixtures commonly used in certain classes of work 
follows : 

TABLE OF RECOMMENDED MIXTURES 

1:1:1 Mixture for 

The wearing course of two-course floors subject 
to heavy trucking, such as occurs in factories, 
warehouses, on loading platforms, etc. 
l:l:l^A Mixture for 

The wearing course of two-course pavements, in 
which case the pebbles or crushed stone is graded 
from 34 to 3^ inch. 



MAKE AND HOW TO USE CONCRETE 25 

1:2:3 Mixture for 

Reinforced concrete roof slabs. 

One-course concrete road, street, and alley pave- 
ments. 

One-course walks and barnyard pavements. 

One-course concrete floors. 

Fence posts. 

Sills and lintels without mortar surface. 

Watering troughs and tanks. 

Reinforced concrete columns. 

Mine timbers. 

Construction subjected to water pressure, such 
as reservoirs, swimming pools, storage tanks, cis- 
terns, elevator pits, vats, etc. 
1:2: 4 Mixture for 

Reinforced concrete walls, floors, beams, 
columns, and other concrete members designed in 
combination with steel reinforcing. 

Concrete for the arch ring of arch bridges and 
culverts; foundations for large engines causing 
heav}^ loading, some impact and vibration. 

Concrete work in general subject to vibration. 

Reinforced concrete sewer pipe. 
1:21^: 4 Mixture for 

Silo walls, grain bins, coal bins, elevators, and 
similar structures. 

Building walls above foundation when stucco 
finish will not be applied. 

Walls of pits or basements subject to consider- 
able exposure to moisture but practically no 
direct water pressure. 



26 THE RAN SOME BOOK — HOW TO 

Manure pits, dipping vats, hog wallows. 

Backing of concrete block. 

Base of two-course road, street, and alley pave- 
ments. 
1:2^:5 Mixture for 

Walls above ground which are to have stucco 
finish. 

Base of two-course sidewalks, feeding floors, 
barnyard pavements, and two-course plain con- 
crete floors. 

Abutments and wing walls of bridges and cul- 
verts, dams, small retaining walls. 

Basement walls and foundations for ordinary 
conditions where water-tightness is not essential. 

Foundations for small engines. 

1:3:6 Mixture for 

Mass concrete, such as large gravity retaining 
walls, heavy foundations and footings. 
1:13^ Mixture for 

Inside plastering of water tanks, silos, and bin 
walls, where required, and for facing walls below 
ground when necessary to afford additional pro- 
tection against the entrance of moisture. 

Back plastering of gravity retaining walls. 
1:2 Mixture for 

Scratch coat of exterior plaster (cement and 
stucco). 

Facing block and similar concrete products. 

Wearing course of two-course walks, floors sub- 
jected only to light loads, barnyard pavements, etc. 



MAKE AND HOW TO USE CONCRETE 



27 



1:2>^ Mixture for 

Intermediate and finish stucco coats. 

Fence posts when coarse aggregate is not used. 
1:3 Mixture for 

Concrete block when coarse aggregate is not 
used. 

Concrete brick. 

Concrete drain tile and pipe when coarse aggre- 
gate is not used. 

Ornamental concrete products. 



QUANTITIES OF MATERIALS REQUIRED FOR 
VARIOUS MIXTURES OF MORTAR 
AND CONCRETE 



Mixture Materials for 
One-Bag Batch 


Resulting 
Volume in 
Cubic Feet 


Quantities of Cement, Sand, and 

Pebbles or Stone required for 

One Cubic Yard of Compacted 

Mortar or Concrete 




Ce- 

ment 

in 

Sacks 


Sand 
cu. ft. 


Peb- 
bles or 
Stone 
cu. ft. 


Mortar 


Con- 
crete 


Cement 

in 
Sacks 


Sand 


Stone or Pebbles 




cu. ft. 


cu.yd 


cu. ft. 


cu. yd. 


1:H 




1.5 




1.75 




15.5 


23.2 


.86 






1:2 




2.0 




2.1 




12.8 


25.6 


.95 






1:2^ 




2.5 




2.5 




11.0 


27.5 


1.02 






1:3 




3.0 




2.8 




96 


28.8 


1.07 






1:2:3 




2.0 


3.0 




3.9 


7.0 


14.0 


.52 


21.0 


.78 


1-2:4 




2.0 


4.0 




4.5 


6.0 


12.0 


.44 


24.0 


.89 


1:2^:4 




2.5 


4.0 




4.8 


5.6 


14.0 


.52 


22.4 


.83 


l:2i:5 




2.5 


5.0 




5.4 


5.0 


12.5 


.46 


25.0 


.92 


1:3:6 




3.0 


60 




6.4 


4.:^ 


12.6 


.47 


25.2 


.94 



28 THE RANSOM E BOOK — HOW TO 

MIXING CONCRETE 

Concrete is mixed either by hand or machine. 
However, on jobs of any size today hand mixing is no 
longer thought of because of the labor involved, and 
also because machine mixing is certain to produce 
more uniformly mixed concrete. There are mjny 
kinds of concrete mixers, but broadly speaking th-se 
may be classified as continuous and batch mixers. 

Continuous mixers, as the name implies, are those 
into which the separate materials are continuously 
fed and from which there is an uninterrupted stream 
of mixed concrete discharged. The idea of the con- 
tinuous mixer is good, but in practice such mixers are 
not reliable. Difference in moisture in the sand, as 
well as packing of the cement in the bin or hopper in 
which contained, is likely to cause varying quantities 
of the materials to be discharged, and therefore the 
resulting concrete will not be uniform. 

BATCH MIXERS 

Engineers now almost invariably specify that con- 
crete be mixed in one of the batch types of mixers. 
This means a mixer into which the separately meas- 
ured quantities of materials are dumped and the 
mixing completed before another supply of materials 
is put in the machine. Ransome mixers are all of the 
batch type and are recognized as the highest class of 
machines in their particular field. Every size and 
kind of mixer may be found in the Ransome line, 
each having its own particular merits with special 
reference to some particular class of work for which 
it is most suitable. 



MAKE AND HOW TO USE CONCRETE 29 

MEASURING MATERIALS 

The most convenient way of measuring the sand 
and pebbles or broken stone is to set a bottomless 
box or frame holding a definite number of cubic feet 
of material into a metal wheelbarrow and then fill 
this box to the required depth or level. Otherwise 
some type of wheelbarrow particularly devised for 
measuring aggregates may be used. It is well to 
determine by one or two test batches the amount of 
water necessary to produce the required consistency, 
then as long as the aggregates being used are the 
same in quality and moisture content the same 
measured volume of water may be used for each 
batch, thus resulting in concrete of uniform con- 
sistency. If the moisture in the sand varies or if 
more porous aggregates must be used, it then be- 
comes necessary to adjust the volume of water used 
for each batch. 

CONSISTENCY OF MIXTURES 

By far too much concrete is mixed either too wet 
or too dry. Rarely is just the right amount of water 
used. In times past the greatest fault of concrete 
construction was dry concrete. In later days and at 
the present time the fault is concrete that is too wet 
— actually sloppy mixtures. For most classes of 
work the correct amount of water is that which will 
produce a concrete of ^^ quaky" or jelly-like con- 
sistency. Less water can sometimes be used for 
foundation concrete where the section is massive or 



30 THE RAN SOME BOOK — HOW TO 

where the wall need not be water-tight, but the 
quaky consistency is preferable wherever possible to 
use it. 

QUANTITY OF WATER 

In hand mixing, batches should not be larger than 
can be conveniently mixed on the platform, nor 
should the batches ever be larger than can be placed 
within thirty minutes after mixing. Water is one of 
the essential ingredients of a concrete mixture. A 
certain quantity is necessary to accomplish the 
chemical change that takes place in the cement when 
combined with water. For ease of working, a little 
in excess of the best quantity necessary may be added 
to make the mass a little more plastic. There are 
differences between the opinions that engineers and 
contractors have as to the correct amount of water to 
be used in concrete mixtures, and as to the effect 
which variations in the quantity of water have on 
the strength and other properties of concrete. The 
amount /of water which gives concrete of maximum 
strength results in a mix which is too stiff to be con- 
veniently used in most work. For example, in plants 
where concrete block, drain tile, and sewer pipe are 
manufactured, it is desirable for profitable output to 
use a mix containing less water than that which 
gives maximum strength. This permits molds to be 
removed within a short time and hence increases 
the output of the plant. 

The exact amount of water necessary for the 
maximum strength of concrete varies with the 
method of handling and placing concrete. The 



MAKE AND HOW TO USE CONCRETE 



31 



proper quantity of water will vary with the quantity 
of cement and the size and grading of the aggregates 
and somewhat on the nature of the aggregates. The 
water required for a sand and crushed stone aggre- 
gate is not greatly different from that required for a 
sand and cement mixture, providing the aggregates 
are similarly graded. If the aggregates are soft or 
porous a somewhat greater quantity of water will be 
necessary. The principal difficulty in attempting to 
state a specific quantity of water for any mixture is 
due to the fact that moisture content and physical 
. characteristics of the aggregates vary. An approxi- 
mation that will help to a decision is given in the 
accompanying table. 



Mix 


Approximate Mix as 
Usually Expressed 


Water Required 
(Gallons per Sack of 


Cement Volume of Aggre- 
1 gate after Mixmg 


Cement 


Aggregate 


Cement) 


Fine ] Coarse 


Minimum 


Maximum 


1 5 

1 41^ 
1 4 
1 3 


1 

1 
1 
1 


2 i 4 
2 I 3 
IV?, 1 3 

IM 1 23^ 


6 

5 


6 

5^ 



Others have stated the quantity of water required 
in a shghtjy different way. The quaky or jelly-like 
consistency can usually be obtained by using water 
in the proportion of one gallon to one cubic foot of 
concrete in place. Some uses of concrete require 
wetter mixtures than are described by the word 
quaky, but never should the quantity of water be 
such as to produce the sloppy consistency which may 
better be described, perhaps, as one which when 
handled on a shovel causes the pebbles to separate 
from the sand-cement mortar. 



32 THE RAN SOME BOOK — HOW TO 

TIME OF MIXING 

Of late years the tendency has been to increase the 
time of mixing. This is a very desirable trend. 
Experiments have proved conclusively that increas- 
ing the time of mixing very greatly influences the 
strength of the resulting concrete. Of course there 
is a limit to the length of time which can be devoted 
to mixing with true economy to the work in question, 
but all concrete would be better if mixed for one and 
one half minutes than one minute or less. Frequently 
a few more turns of the drum will produce the re- 
quired consistency, which is often obtained at a 
sacrifice of strength of the concrete by using more 
water than needed and reducing the time of mixing. 

Before water is added to the materials in the drum 
it should be given a few revolutions to thoroughl}^ 
mix the materials while dry. Then the required 
amount of water should be added and the drum 
revolved for a specified time or a specific number of 
revolutions. Many mixers have attached to them a 
water tank by means of which a measured quantity 
of water for each batch may be added to the dry 
materials. 

Care should be taken not to place more materials 
in the drum than recommended by the manufac- 
turers, as proper mixing cannot then be accom- 
plished. When the batch has been completely mixed 
its volume in the drum should not represent more 
than one third of the total cubic capacity of the 
drum. Many contractors fail to understand mixer 
capacity. They do not realize how much greater 



MAKE AND HOW TO USE CONCRETE 33 

is the volume of unmixed materials as they lie in the 
drum before it has been revolved than the resulting 
volume of concrete. This is a simple matter and can 
readily be understood by recalling statements 
previously made with reference to the voids in the 
various materials. Until the measured materials 
have been mixed they represent a volume cor- 
responding to the total number of cubic feet of the 
several materials measured separately; that is, until 
mixed a 1 :3 :5 mixture has nine cubic feet of materials. 
Just as soon as mixing begins, however, the distri- 
bution of the smaller sized particles amongst the 
larger ones commences to fill the voids or air spaces 
in the mass and considerably reduces its volume. 

FORMS FOR CONCRETE 
GENERAL 

When a batch of concrete is mixed, it must be 
placed in some kind of a form or mold that mil give 
it the desired shape. Practically every class of 
concrete work requires form construction, the only 
exception to this being that sometimes concrete for 
a foundation may be placed in a trench \\dthout 
forms, providing the excavation walls are firm and 
self-supporting. For work above ground and for 
concrete objects in general some kind of forms or 
molds are necessary. 

TYPES OF FORMS 

In the average run of concrete work wood forms 
are used. For work such as circular tanks, silos, and 



34 THE RAN SOME BOOK — HOW TO 

other circular structures, there are various types of 
metal forms on the market devised with special 
reference to the classes of work above mentioned. 
There are also various types of so-called form sys- 
tems, most of which are patented and involve metal 
forms. Because of the fact that no two concrete 
structures are rarely, if ever, exactly alike, wood 
forms are used more often than metal forms. Some- 
times where an exceptionally smooth surface finish is 
desired, and it is also advisable to prolong the life of 
the forms so they may be used repeatedly on similar 
portions of different buildings, they are lined or 
covered inside with thin sheet steel. 

REQUIREMENTS OF WOOD FORMS 

Depending upon the nature of the work, its mas- 
siveness, and hence the volume of concrete to be sup- 
ported, forms are made of lumber varying from one 
inch to two or three inches in thickness. This refers 
to the form sheathing itself. Braces, studs, and 
posts to which sheathing is nailed may be two by 
four inches, two by six inches, or any similar dim.en- 
sions that will withstand the loads or strains that will 
be brought upon forms by the concrete in place before 
it has hardened and become self-supporting. 

Norway pine, spruce, and southern pine are the 
most generally used and economical form lumbers. 
Short leaf pine also makes good form sheathing. If 
spruce can be obtained it is probably the best 
material to use for studs, braces, joists, and posts, 
as it is tough under bending strains. Hemlock is too 



MAKE AND HOW TO USE CONCRETE 35 

coarse grained for sheathing and sphts easily, so is 
not reliable for heavy frame work. The hard woods, 
such as oak, are too high priced and too difficult to 
work economically. 

Form lumber should be free from imperfections, 
such as shakes, rot, and knots, especially where the 
appearance of the finished work is of importance. 
Unplaned lumber will do where the concrete surface 
is to be hidden from view, but planed lumber is 
always best because of the smoother surface finish 
that can be secured on the concrete and also because 
the concrete will stick less to the forms. Air-seasoned 
lumber is better than kiln dried. The latter will 
swell and bulge at joints, while if the lumber is green 
it will shrink very quickly in drying out, after forms 
are made, thus opening cracks through which water 
carrying cement will leak out when the concrete is 
placed. Lumber dressed on both sides and edges 
may sometimes be necessary, because it is very im- 
portant that sheathing boards be of uniform thick- 
ness; otherwise when nailed to the studs the inside 
face of forms will be very irregular and this irregu- 
larity will be reproduced in the concrete surface, 
making it unsightly. Tongued and grooved materials 
and what is known as shiplap are often used for form 
sheathing. Beveled edge stock has its advantages, 
because if the lumber swells the edges will slip past 
each other without causing warping or bulging of 
the boards. Beveled edge stuff is usually cheaper, 
because there is less waste in manufacturing at the 
mill, 



36 



THE RAN SOME BOOK — HOW TO 



SAFE LOAD FOR STUDS OR POSTS 

Posts and studs for supporting forms must be 
strong and stiff enough to hold them in true Hne and 
to prevent sagging under the load of concrete. The 
maximum safe load for wood posts of various lengths 
and sections is given below. Knowing the length of 
post, total weight of concrete and forms to be sup- 
ported, and the economical number of posts, the 
load per post can readily be determined. It should 
be remembered that a corner post carries over one 
fourth of the load carried by a side post and that a 
side post carries one half the load of an inside post. 

TABLE I 

Maximum Safe Load in Pounds for Wood Colimms 



Length in ft. 


4 in. 


6 in. 


8 in. 


5 


9,400 






6 


8,800 






7 


8,200 






8 


7,500 


20,700 




9 


6,800 


19,800 




10 


6,300 


18,900 


37,700 


11 




17,900 


36,400 


12 




17,000 


35,200 


14 




15,100 


32,700 


16 






30,200 


18 






27,600 


20 






25,100 



Example : 

Flat slab 14 feet by 17 feet 8 inches, weighing 
approximately 60,000 pounds, 16 post can be spaced 
economically in four rows of 4. There will be 4 cor- 
ner posts, 8 side posts, and 4 inside posts — 16 posts. 



MAKE AND HOW TO USE CONCRETE 37 

4 corner posts carry load of 1 inside post = 1 

8 side posts carry load of 4 inside posts = 4 

4 inside posts carry load of 4 inside posts = 4 

Number posts of equal load 9 

Maximum load per post= ^^^= 6,666 lb. 
Length of post 6 feet inches. 

From the table we find one 4 by 4 inch post 6 feet 
long will carry safely a load of 8,800 pounds. Since 
no timbers of less than 4 by 4 inches should be used, 
this size wdll be adopted. 

PLANNING FORMS ECONOMICALLY 

Considerable economy in form work results from 
carefully planning the forms before cutting lumber. 
Often form units can be planned that will serve 
repeated use on similar portions of structures other 
than the one for which first made. Any such fore- 
thought given the planning of forms will therefore 
result in final economy. For some work but httle 
cutting may be required. Stock lengths can be used 
and ends allowed to hang over without causing any 
inconvenience on the job. Also, if the forms are 
planned so that few nails will be necessary to hold 
them together, less damage will be done to lumber 
when knocked apart than if tightly nailed together. 
Often screws can be used to decided advantage 
instead of nails. 

Bolts, clamps, and various kinds of ties can also 
be used on some types of forms, thus making any 
permanent fastenings entirely unnecessary. Such 



38 THE RAN SOME BOOK — HOW TO 

devices where they can be used make form lumber 
last longer. The forms or the lumber can be reassem- 
bled for other forms, serving repeated use on a num- 
ber of structures and thus reducing the cost of form 
work on each job. Waste of lumber in concrete form 
work results often from allowing carpenters un- 
familiar with concrete work to make the forms. For 
important jobs quite a different kind of carpenter 
skill is required than is usually possessed by a car- 
penter whose experience has been on fine permanent 
structures built throughout or largely of wood. The 
experienced form carpenter bears in mind that forms 
can be designed so that some if not most of the 
lumber can be used again. Therefore he is careful 
to avoid unnecessary cutting and other damage to 
lumber. 

COST OF FORM WORK 

Straight walls and flat floors usually require the 
simplest types of forms. In normal times such forms 
can often be built for from $10 to $20 per thousand 
feet board measure of lumber. If there are many 
corners, openings, offsets, projections, and similar 
irregularities, to be molded in the concrete surface 
or section, there must be more cutting of lumber, 
which will correspondingly increase the cost of forms. 
In normal times form lumber can be obtained for 
from $25 to $30 per thousand feet board measure. 
The longer it can be used the less the amount of its 
original cost will be charged to any one job. 

As has been mentioned, economy in cost of forms 
can often be brought about by planning unit sections 



MAKE AND HOW TO USE CONCRETE 39 

so far as possible, that is, panels which can be reset 
on the same job in similar position without altera- 
tion. This is especially true in plain wall construc- 
tion, beams, floor slabs, and columns. There are on 
the market a number of types of unit forms for 
various classes of construction. These permit 
building both solid (monolithic) and hollow walls. 
Among the common types of unit forms are those 
used for silos, arches, sewers, and box culverts. 
Many of these are adjustable so as to permit being 
used for structures of the types mentioned, having 
different dimensions. 

WETTING OR GREASING FORMS 

After forms are set up and firmly braced in posi- 
tion they should be either wet down or slightly 
greased with a mixture of linseed oil and kerosene, or 
some other application, so that concrete will not 
stick to them. Each time after use the forms should 
be thoroughly cleaned, and before again used should 
be wet down or wiped with oil immediately before 
concrete is placed in them. 

IMPORTANCE OF BRACING FORMS 

Some failures of concrete work have had their 
origin in faulty form construction. This is par- 
ticularly true of floors and arches. Form studs or 
supports were not strong enough to hold the load of 
concrete, and a gradual settlement or change in 
position of forms while the concrete has been under- 
going early hardening produced small cracks in the 



40 THE RAN SOME BOOK — HOW TO 

concrete. These naturally increase in size just as 
soon as the structure is loaded, and frequently failure 
has followed. This leads up to the subject of form 
removal. 

FORM REMOVAL 
Concrete failures have resulted from too early 
removal of forms. It should be remembered that 
concrete hardens quite differently under different 
weather and temperature conditions. Moist, warm 
weather is most favorable to the rapid hardening of 
concrete. Cold weather retards hardening greatly, 
depending upon the degree of cold. For example, it 
might be safe to remove forms in from twenty-four 
to forty-eight hours from some piece of work in warm 
weather, while it might be necessary to leave forms 
in place for two or three weeks in cold weather. It 
is particularly important not to remove forms from 
concrete that is to be self-supporting, such as floors, 
roof slabs, and arches, until all possibility of failure 
has passed. Forms may often be removed from 
vertical walls within twenty-four hours after the last 
concrete was placed, but forms for arch rings, roof 
slabs, and floors may have to be left in place for a 
week or several weeks to make certain that the con- 
crete has properly hardened so as to be able to sup- 
port not only its own weight but that of any load 
that may be placed upon it immediately after forms 
are removed. No specific rule can be laid down for 
the time which must elapse before forms may safely 
be removed. This is something which only experience 
and good judgment can determine. 



MAKE AND HOW TO USE CONCRETE 41 

REINFORCING CONCRETE 

PRINCIPLES OF REINFORCING 

It is presumed that those who will read this book 
know why concrete is reinforced, therefore the sub- 
ject will not be discussed at length; an outline of the 
principles will be sufficient. Concrete is relatively 
weak in tension or in resisting strains that tend to 
pull it apart. It is also weak in resisting bending 
strains. In bearing loads that are placed directly 
upon it, concrete is very strong, that is, it has a 
great compressive strength. To take advantage of 
concrete's full compressive strength, regardless of 
how the material may be used in any portion of a 
building, it is necessary to embed steel in it to resist 
bending or pulling strains, that is, strains of tension. 
Each concrete structure is the subject of a particular 
design, so, except as relates to some standard sections 
or portions of fixed dimensions, it is not possible to 
la}^ down definite rules for reinforcing concrete. 

LOCATION OF REINFORCEMENT 

In every use of reinforcement it is necessary that 
the material be placed in the concrete at some 
particular point or location to secure its full effective- 
ness. In a beam, for example, the reinforcement is 
placed along its lower section, sufficiently embedded 
in the concrete to prevent injury from severe ex- 
posure to fire, for instance. Usually from one to one 
and a half inches of such protection is all that is 
necessary. The principal thing to observe when 



42 THE RAN SOME BOOK — HOW TO 

placing reinforcing is to make sure that its location 
in the forms with reference to the position that it is 
to occupy in the finished concrete work is exactly in 
accordance with the position shown on the engineers' 
or designers' plans from which the contractor is 
working. This is necessary for several reasons — 
protection against fire, for example- — but princi- 
pally because the engineer or designer has calculated 
that the quantity and size of steel specified will best 
accomplish its purpose in the location shown for it 
on the plans. Therefore in placing concrete for 
reinforced work it is very important that the steel 
when laid in position in the forms shall not be dis- 
placed when the concrete is deposited. 

Bars and mesh used for reinforcement can be 
blocked up into proper position by placing beneath 
them small cubes of concrete which may afterward 
be left in the work. If wood blocks are used for the 
same purpose, they should subsequently be removed 
and the space which they occupied be filled with a 
good, rich sand-cement mortar. 

MATERIALS USED AS REINFORCEMENT 

Various materials are used for reinforcing con- 
crete, that is, steel is used in various forms. There 
are plain, round, and square rods, twisted square 
rods, and various other types of round and square 
rods that are in different ways deformed, so to speak, 
when they are manufactured. They have lugs or 
projections molded in their surface, the idea of this 
deforming being to increase the mechanical bond 



MAKE AND HOW TO USE CONCRETE 43 

between the concrete and steel. In some cases de- 
formed bars may be best, as they are a safeguard 
when concrete has not everywhere been puddled or 
spaded to place around the bars, as it should be; 
also, when for any reason the consistency of the 
concrete is drier than would be best. In some 
cases mechanically deformed bars are a safeguard 
against slight variations in the workmanship or 
placing concrete. If, however, concrete is of correct 
consistency, and is sufficiently rich in cement, the 
natural bond between " concrete and plain round or 
square rods is enough to take advantage of the safe 
elastic hmit of the steel. For most work round, 
square, or twisted square rods or bars are satisfactory 
and most commonly used because easiest to obtain. 

EXPANDED METAL AND MESH FABRIC 

Other types of reinforcing used largely for certain 
classes of work, such as floor and wall construction, 
roof slabs, and for ground work for stucco, are the 
various deformed or expanded sheet metals, steel 
wire mxcsh, and similar fabrics. Most of these rein- 
forcing materials have unusual merits if properly 
used, and they also have a wide range of use. In a 
great many cases some one of the fabrics or expanded 
metals can be substituted for steel rods or bars, 
providing the net sectional area of the materials 
substituted is equivalent to that of the .rods or bars. 

Generally speaking, the average contractor need 
consider but one grade of reinforcing steel. This 
can be obtained direct from any of the steel com- 



44 THE RAN SOME BOOK — HOW TO 

parties or through dealers in the usual variety of 
building materials. It should be remembered that 
there is a great variation in steel, that is, there are 
many grades of it. Some steel is quite like wrought 
iron, while others may be compared with cast iron 
as. regards brittleness. This should lead one to 
realize that not all steel is suitable for reinforcing 
concrete. Reinforcing steel should meet certain 
specifications which have been laid down by engi- 
neering societies, notably the American Society for 
Testing Materials. Such steel ranges in tensile 
strength from 55,000 to 70,000 pounds per square 
inch. The stocks of steel often carried by hardware 
stores, and particularly by local blacksmith shops, 
are not of the desired quality for reinforcement in 
concrete. When steel of a certain tensile strength or 
having other particular qualities is called for in a 
specification the contractor or builder should make 
certain that the material he is using meets the 
requirements set forth. 



CARE OF REINFORCEMENT BEFORE USE AND 
ON THE JOB 

Reinforcing steel or other reinforcing materials 
must be handled on the job properly. The steel 
must be placed exactly where it belongs in the con- 
crete. Care should be taken to see that before 
placed all loose rust or mill scale is removed from it 
by brushing with wire brushes or pickling in a weak 
acid bath and then washing thoroughly with clean 



MAKE AND HOW TO USE CONCRETE 45 

water; also that it is not covered wholly or in part 
with oil or grease. Any of the foregoing will prevent 
good bond or adhesion between concrete and steel. 

Reinforcing material should not be bent suddenly. 
Various types of machines are on the market intended 
for use in cutting, bending, and otherwise shaping 
reinforcing bars according to the requirements of 
plans. Reinforcing for many members of buildings 
are often furnished completely assembled so that 
they can be readily set up in the forms. Bending 
has all been done properly and this leaves but little 
work to do on the job. If bars must be bent on the 
job, proper machines should be used for the purpose 
and the bending should be done steadily and 
gradually, so that the steel is not subjected to sudden 
jerks or twists that might tend to start a fracture at 
the point where bent and thus weaken the rein- 
forcement. 



CONVENIENT CONCRETE ESTIMATING TABLES 
AND EXAMPLES 

For convenience, concrete is usually mixed in 
batches, each requiring one sack of cement. The 
following table shows the cubic feet of sand and 
pebbles (or crushed stone) to be mixed with one 
sack of cement to secure mixtures of the different 
proportions indicated in the first column. The last 
column gives the resulting volume in cubic feet of 
compacted mortar or concrete. 



46 THE RANSOME BOOK — HOW TO 

TABLE No. I 



MIXTURES 


MATERIALS 


COL. IN CU. FT. 


Cement 


Sand 


Pebbles 
or Stone 


Cement 
in Sacks 


Sand 
cu. ft. 


Pebbles 

or Stone 

cu. ft. 


Mortar 


Concrete 




1.5 

2 

3 

1.5 

2 

2 

2.5 

2.5 

3 


3 
3 
4 
4 
5 
5 




1.5 

2 

3 

1.5 

2 

2 

2.5 

2.5 

3 


3 
3 
4 
4 
5 
5 


1.75 
2.1 

2.8 


3.5 
3.9 
4.5 

4.8 
5.4 

5.8 



The following table gives the number of sacks of 
cement and cubic feet of sand and pebbles (or stone) 
required to make one cubic yard (twenty-seven cubic 
feet) of compacted concrete proportioned as indi- 
cated in first column. 



TABLE No. II 




MAKE AND HOW TO USE CONCRETE 47 

EXAMPLE I 

How much cement, sand, and pebbles will be re- 
quired to build a feeding floor 30 by 24 feet, 5 inches 
thick? 

Multiplying the area (30 by 24) by the thickness 
in feet gives 300 cubic feet, and dividing this by 27 
gives lli cubic yards as the required volume of 
concrete. A one-course floor should be of 1:2:3 
mixture. Table II shows that each cubic yard of 
this mixture required 7 sacks of cement, 14 cubic 
feet of sand, and 21 cubic feet of gravel or stone. 
Multiplying these quantities by the number of cubic 
yards required (Hi) gives the quantities of 
material required (eliminating fractions) as 78 sacks 
of cement, 156 cubic feet of sand, and 233 cubic 
feet of pebbles or stone. As there are 4 sacks of 
cement in a barrel, and 27 cubic feet of sand or 
pebbles in a cubic yard, we shall need a little less 
than 20 barrels of cement, 6 cubic yards of sand, 
and 9 cubic yards of pebbles or stone. 

EXAMPLE II 

How many fence posts 3 by 3 inches at the top, 
5 by 5 inches at the bottom, and 7 feet long can be 
made from, one sack of cement? How much sand 
and pebbles will be needed? 

Fence posts should be of a 1 :2: 3 mixture. Table I 
shows the volume of a one-sack batch of this mixture 
to be 3-ro cubic feet. The volume of one concrete 
post, found by multiplying the length by the average 
width and breadth in feet (7 by i by I) is | cubic 



48 THE RAN SOME BOOK — HOW TO 

foot. By dividing 3iV by ^ we find that five posts 
can be made from 1 sack of cement when mixed 
with 2 cubic feet of sand and 3 cubic feet of 
pebbles. 

EXAMPLE III 

What quantities of cement, sand, and pebbles are 
necessary to make 100 unfaced concrete blocks, each 
8 by 8 by 16 inches? 

The product of height, width, and thickness, all in 
feet (I by | by |) gives \j cubic foot as the 
contents of a solid block. As the air space is usually 
estimated as 33|^ per cent, the volume of concrete 
in one hollow block will be f or ^f or ff cubic 
foot; in 100 blocks the volume of concrete will be 
-|f^ or 39K cubic feet, which being divided by 27 
gives a little less than V/2 cubic yards. Unfaced 
concrete block should be of 1:23/^:4 mixture. Table 
II shows that each cubic yard of this mixture requires 
5tV sacks of cement, 14 cubic feet of sand, and 
22xV cubic feet of pebbles. Multiplying these quan- 
tities by the number of cubic yards required (1)^) 
gives the quantities of material required as 8f sacks 
of cement, 21 cubic feet of sand, and 33f cubic 
feet of gravel. 

EXAMPLE IV 

How many 6 foot hog troughs 12 inches wide and 
10 inches high can be made from 1 barrel of cement? 

Use a 1:2:3 mixture. Table I shows the volume of 
a 1 sack batch of this mixture to be Sy^o cubic 
feet. As there are 4 sacks in 1 barrel, a. barrel of 



MAKE AND HOW TO USE CONCRETE 49 

cement would be sufficient for four times Sro, or 
15iS" cubic feet of concrete. The product of the 
three dimensions, all in feet, gives the volume of one 
trough as 5 cubic feet. However, approximately 
30 per cent of this volume is in the open water basin 
or inside of the tank, leaving 3 1\ cubic feet as the 
solid contents of concrete in one trough. Dividing 
15tV by Sj-Q, we find that 4 troughs (and a 
fraction over) can be made from 1 barrel of cement 
when mixed with 8 cubic feet of sand and 12 cubic 
feet of pebbles. 

PLACING CONCRETE 
GENERAL 

The hardening which takes place when cement 
and water are combined is noticeable within a very 
short time after a batch of concrete has been mixed. 
For this reason concrete should be deposited as 
quickly as possible after mixing. No concrete should 
be used when it is thirty minutes or more old. 

METHODS OF PLACING 

Methods of placing necessarily vary in accordance 
with the class of work and the condition under which 
it is being carried on. Concrete should be de- 
posited in a layer or layers of uniform depth, as for 
instance when a foundation wall is being built, or 
arrangements should be made to fill up one section 
of the forms at a time, provision being made at one 
end of the section to join the next one to it so a 
water-tight joint ^^dll result. 



50 THE RANSOME BOOK — HOW TO 

Concrete for pavements and for floors on the 
ground is generally dumped from wheelbarrows or, 
in the case of highway pavements, is placed by a 
spout or by means of a boom and bucket. In street 
and highway pavement work the subgrade should be 
thoroughly sprinkled before concrete is placed, so 
that the concrete will not be robbed of water. 

Where the only surface finish required is that 
obtained from contact with the forms, the concrete 
should be spaded with some chisel-edged tool used 
next to form faces so as to force back coarse particles 
of aggregate and allow the fine sand-cement mortar 
to come next to the form, thus producing a smoother, 
denser, and hence water-tight surface. 

Where surfacing mixtures are used it is necessary 
to place the facing mixture a little in advance of the 
back or center of the work either by hand or by 
means of a metal septum. Then the septum is with- 
drawn and the center mass consolidated by tamping 
or spading so that it will thoroughly unite with the 
facing mixture. To best accomplish this the two 
mixtures should be of as nearly the same con- 
sistency^ as possible. 

Care should be taken not to dump concrete into 
the forms through too great a height. If it is dropped 
more than 6 or 8 feet the materials are likely to 
separate somewhat in falling and this will cause 
pebble pockets in the work. 

Much poor concrete work has been done byplacing 
concrete through spouts. In such cases elevators 
are run up towers, the concrete dumped into a 



MAKE AND HOW TO USE CONCRETE 51 

hopper connected with the spout and allowed to 
flow down through the spout into place. The object 
of such placing is to make one central plant distribute 
concrete over as large an area as possible without 
changing the location of the central plant frequently. 
Spouts are frequently made to cover too wide a 
range, with the result that they lie at too flat an 
angle and then too much water is used in the mixture 
to make the concrete travel in the spout. Spouting 
concrete into place permits rapid and economical 
placing, but the concrete must not be sloppy. Care 
should therefore be taken never to set spouts at a 
flatter angle than will carry concrete of the right 
consistency. This is usually about twenty-five 
degrees. 

Concrete is also placed by compressed air. The 
Ransome Concrete Machinery Co. manufactures a 
pneumatic placing machine for this purpose which 
has special efficiency in that it both mixes the con- 
crete and places it with force at the right consistency, 
thus practically doing away with the need of tamping 
or spading in the forms. 

Concrete should not be placed in layers deeper than 
will permit firmly consolidating it with concrete 
previously placed. Nor should the operation of 
placing be interrupted so that concrete previously 
placed has commenced to harden before that sub- 
sequently placed is put upon it. If such is the case 
the two layers cannot be made to unite thoroughly. 
Such conditions produce construction seams in the 
work, which not only we-aken it but are quite likely 



52 THE RAN SOME BOOK — HOW TO 

to be the cause of leakage. When necessary to dis- 
continue concreting before forms are filled, as at the 
end of the day, for instance, the top of the concrete 
last placed in the forms should be roughened by 
scratching it with a stick to prepare for a good bond 
with the concrete that is to be placed later. Im- 
mediately before resuming concreting the surface of 
the old concrete should be well scrubbed and washed 
with a broom and water, and painted with a mixture 
of cement and water of about the consistency of 
thick cream, this being done immediately before 
placing new concrete. 

Arrangements should be made wherever possible 
to carry on continuously the concreting of tanks, 
silos, reservoir walls, and any concrete work that has 
to be water-tight, so as to prevent the construction 
seams mentioned. However, on some work it is 
necessary to suspend concreting each day. Then 
the work should be left roughened in the forms and 
treated as previously described. On tank work some 
have found it advisable to embed at or along the 
center line of the concrete section a strip of tin or 
sheet iron half into the concrete just placed, and half 
exposed preparatory to being covered with concrete 
the next day. Just before resuming work this metal 
strip as well as the old concrete should be painted 
with the creamy cement-water paint previously 
mentioned. 

PROTECTING THE FINISHED WORK 

Proper protection of concrete after placed is of the 
utmost importance. Concrete mixtures may have 



MAKE AND HOW TO USE CONCRETE 53 

been properly proportioned, may have been mixed 
to the correct consistency, and may have been 
properly placed, yet if the concrete is allowed to dry 
out or in any other way lose the water which was 
combined with it, the cement is deprived of the 
ingredient necessary to hardening, hence the concrete 
will lack strength and water-tightness. 

The hardening of concrete is not a drying process, 
as some people suppose. If concrete after being 
placed is left exposed to sun and wind much of the 
water necessary to its hardening is lost by evapora- 
tion. Protection is especially necessary on floors 
and walls where considerable surface area is exposed. 
It is not so necessary on mass work, since such work 
is to a certain extent self-protecting. Floors, walks, 
pavements, and like work should be protected by a 
covering of moist earth or some other moisture- 
retaining material. This should be kept wet for 
several days, when it may be removed and the con- 
crete allowed to harden naturally. The ideal con- 
ditions for hardening of concrete are warmth and 
moisture. When these two conditions are present 
the concrete hardens most uniformly. An illustra- 
tion of this is seen in the practice of ponding or 
flooding concrete road pavements immediately after 
they have hardened sufficiently to permit covering 
with water. 

Thin wall sections may be given part of the pro- 
tection needed by leaving forms in place a day or two 
longer than ordinarily would be necessary and 
wetting down the entire work several times daily. 



54 THE RAN SOME BOOK — HOW TO 

Silo and tank walls should be protected by hanging 
canvas cloth over them and keeping this wet. Stucco 
should be protected in the same manner. Indeed a 
great deal of the hair-cracking in stucco work is due 
to the almost universal practice of omitting protec- 
tion against sun and wind immediately after the 
work is finished. 

Until contractors and others realize the full im- 
portance of these protective measures there will be 
more or less concrete work that will be the subject 
of unjust criticism as far as concrete itself is con- 
cerned. 

CONCRETING IN COLD WEATHER 

Many concrete contractors now keep their plant 
operating practically twelve months a year by taking 
precautions in their concrete work to observe 
practice that makes concreting in cold weather just 
as successful as that done in warm weather. 

The principles underlying the success of concrete 
work done in cold weather are the following: 

Sand and pebbles or broken stone used must be 
free from frost or lumps of frozen materials. If there 
is frost or frozen lumps in the materials they must be 
thawed out. 

Sand and pebbles or broken stone and mixing 
water must be heated. Cement forms only a small 
bulk of the materials in a batch of concrete and need 
not be heated. 

It is necessary to mix, place, and protect the con- 



MAKE AND HOW TO USE CONCRETE 55 

Crete, so that early hardening will be complete 
before the work is exposed to freezing temperatures. 

Sand and pebbles, or broken stone, and mixing 
water should be heated so that the concrete when 
placed has a temperature of seventy-five to eighty 
degrees. 

Adding common salt to the mixing water will pre- 
vent freezing of concrete that has not hardened. 
There is a limit to the quantity of salt which may be 
used, however, as an excess will affect the final 
strength of the concrete. Salt is not desirable, as it 
simply lowers the freezing point of the mixing water. 
It does not supply what is most needed — heat and 
warmth. It delays instead of hastens hardening of 
the concrete. 

Some sands and pebbles or broken stones are 
injured by too much heat. Temperature not ex- 
ceeding 150 degrees Fahrenheit will generally be 
high enough when heating these materials. 

Concrete must be placed immediately after mixing, 
so that none of the heat will be lost before placing in 
the forms. 

Metal forms and reinforcing steel should be 
warmed before placing concrete. Snow and ice and 
frozen concrete remaining on the forms from pre- 
ceding work should be removed. Forms can be 
warmed by turning a jet of steam against them or by 
wetting with hot water. 

Unless the work is protected immediately after 
placed it will lose much of the heat. Canvas cover- 
ing, sheathing, housing in the work, or hay or straw 



56 THE RAN SOME BOOK -HOW TO 

properly applied, will furnish protection for some 
work. Small oil or coke burning stoves or sala- 
manders are used to supply the necessary heat in 
enclosed structures. 

Temperatures which may not be low enough to 
freeze the concrete may delay its hardening for some 
time. Concrete placed when the temperature is low 
and remains low for some time afterward will not 
be safe under load as soon as though placed during 
warmer weather. 

Concrete which freezes before early hardening has 
been completed may not be permanently injured if 
after thawing out it is not again exposed to freezing 
until hardened. However, it is best to protect the 
concrete as soon as placed, so that it- will not freeze. 
Alternate freezing and thawing at comparatively 
short intervals will seriously damage concrete that 
has not hardened. Forms must not be removed 
from concrete work done during cold weather too 
early. This applies to any concrete work regardless 
of season, but is particularly important in cold 
weather concreting. 

Frozen concrete sometimes very closely resembles 
concrete that has thoroughly hardened. When 
frozen concrete is struck with a hammer it will often 
ring like properly hardened concrete. Work should 
be carefully examined before removing forms. The 
flame of a blowtorch, a steam jet, or hot water 
applied to the concrete will show whether it is 
merely frozen or has hardened. If frozen, heat will 
soften it by thawing the water contained in it. 



MAKE AND HOW TO USE CONCRETE 57 

PLACING CONCRETE UNDER WATER 

Sometimes concrete must be placed under water. 
In such cases the methods must be such that the in- 
gredients will not be separated. Some kind of a 
spout or a large pipe must be used to carry the con- 
crete to a point near the bottom of the water, the 
pipe being gradually withdrawn as the concrete is 
built up. Other^dse large buckets are used which 
are lowered to and opened at the place of deposit. 
Concrete to be placed under water should not be 
mixed too wet. Difficulty often experienced with 
placing concrete under water comes from lack of 
care to prevent separation of cement and aggre- 
gates. Concrete cannot be thrown on the surface 
of the water and allowed to settle through it, because 
separation of materials is then certain. 

One common and practical method of placing 
under water is to provide a closed rectangular wood 
chute or circular metal one, called a tremie. This is 
placed with one end extending into the water to the 
foundation in such a manner as to prevent concrete 
from flowing out while the chute is being filled with 
concrete. A^^en entirely filled, it is raised slightly, 
thereby permitting the concrete to distribute itself 
and at the same time permit additional concrete 
being placed in the chute, so that depositing is con- 
tinuous ^^and the entrance of water to the chute pre- 
vented. In large work a closed bucket with hinged 
bottom is often used. When the bucket reaches the 
bottom, or foundation, its bottom is released and 
the concrete falls into position. 



58 THE RAN SOME BOOK — HOW TO 

Concrete has been placed by first filling sacks 
which were lowered through the water to the foun- 
dation. This, however, is not good practice, as good 
bond cannot be secured through different parts of 
the foundation. When the concrete is to be deposited 
from the air by a receptacle lowered into the water, 
it should be mixed dry enough so when the gate or 
trap door of the bucket is opened the material will 
be discharged in a mass. Sometimes cofferdams are 
used to prevent current where the concrete is de- 
posited. The water should always be kept quiet. 
The surface of the concrete under water must be kept 
as nearly level as possible to avoid the formation of 
pockets which will retain sediment or silt. Freshly 
deposited concrete should not be disturbed. If the 
concrete is not deposited continuously, all sediment 
should be removed from the surface of the concrete 
by pumping or otherwise before resuming additional 
concreting. 

ACTION OF SEA WATER ON CONCRETE 

Opinions on this subject often seem contradictory. 
However, extensive investigation of the subject has 
proved that the success of concrete in sea water 
depends largely, if not entirely, upon certain well 
defined practice. Concrete must be dense, rein- 
forcing steel must be placed far enough from the 
surface so that sea water will not come in contact 
with it and start oxidization or rusting which will 
eventually cause bursting of the concrete on the 



MAKE AND HOW TO USE CONCRETE 59 

face. Rich mixtures should be used throughout, 
otherwise a rich facing mixture should be placed 
simultaneously with the mass concrete. AVhere dis- 
integration of concrete in sea water has been ob- 
served it has generally been proved that the concrete 
lacked density, also that disintegration was more 
marked between high and low water marks, indi- 
cating that the salts in the sea water entered the 
pores of the lean concrete and caused rupture by 
crystallizing when the water evaporated. 

The United States Bureau of Standards, Tech- 
nologic Paper No. 12, says: 

The disintegration of cement structures when 
placed in contact with sea water is a phenomenon 
which has attracted the attention of cement 
manufacturers and cement users almost from 
the first time that such material was used for 
marine construction. There are cement struc- 
tures which have withstood the action of sea 
water for years, and probably will continue to 
do so, yet there are structures which have 
failed; and it is also possible in the laboratory 
by artificial solutions to destroy almost com- 
pletely a briquette, or cube, or cylinder made of 
cement mortars or concrete. The cause of this 
disintegration is not certain, though it is almost 
universally believed that it is the reaction of 
sulphate of magnesia of the sea water with the 
lime of the cement (formed during the setting) 
and the alumina of the aluminates of the cement, 



60 THE RAN SOME BOOK — HOW TO 

resulting in the formation of hydrated magnesia 
and calcium sulpho-aluminate, which crystal- 
lizes with a large number of molecules of water. 

The other constituents both of the sea water 
and the cement are usually considered of little 
effect, though lately attention is being drawn to 
the fact that both sodium chloride and mag- 
nesium chloride rapidly attack the silicates. 

Portland cement mortar or concrete, if porous, 
can be disintegrated by the mechanical forces 
exerted by the crystallization of almost any salt 
in its pores, if a sufficient amount of it is per- 
mitted to accumulate and a rapid formation of 
crystals is brought about by drying; and as 
larger crystals are formed by slow crystalliza- 
tion, there would be obtained the same results 
on a larger scale, but in greater time, if slow 
drying were had. Porous stone, brick, and other 
structural materials are disintegrated in the 
same manner. ... 

Properly made Portland cement concrete, 
when totally immersed, is apparently not sub- 
ject to decomposition by the chemical action of 
sea water. 

While these tests indicated that Portland 
cement concrete exposed between tides resisted 
chemical decomposition as satisfactorily as the 
totally immersed concrete, it is felt that actual 
service conditions were not reproduced, and 
therefore further investigation is desirable. . . . 

Marine construction, in so far as the concrete 



MAKE AND HOW TO USE CONCRETE 61 

placed below the surface of the water is con- 
cerned, would appear to be a problem of 
method rather than materials, as the concrete 
sets and permanently hardens as satisfactorily 
in sea water as in fresh water or in the atmos- 
phere, if it can be placed in the forms without 
undue exposure to the sea water while being 
deposited. 

CONCRETE FLOORS 

GENERAL 

Concrete floors are a t3^e of pavement. Some- 
times they are laid on the ground, and in others, as in 
reinforced concrete buildings, are aboveground. 
Concrete floors have in instances been cause for 
complaint. One of the common objections to them 
is that under heavy traffic they ''dust" more or less. 
Dusting is the result of neglect to observe one or 
more of the fundamental requirements of concrete 
construction. Usually the concrete mixtures are 
either too wet or too dry. In the first case, finishing 
operations must be gone through several times in 
order to give the floor the desired finish. Repeated 
trowehng draws too much fine cement to the surface. 
This takes the wear, and not being so resistent to 
wear as aggregate particles, comes off and causes the 
dust spoken of. Too dry a mixture lacks the quan- 
tity of water needed to transform the cement chemi- 
cally, so that it will act as the firm, durable binder 
which it really is when properly used. 



62 THE RAN SOME BOOK — HOW TO 

CAUSES OF DUSTING 

The common causes of dusting of concrete floors 
are: 

Too fine, dirty, or otherwise unsuitable sand. 

Too little cement in the mixture. 

Too much time allowed to elapse between mixing 
and finishing. 

Troweling at several intervals after hardening has 
commenced. 

The use of driers, and, finally 

Neglect to protect the floor (keep it moist) for 
several days after concreting has been finished. 

TYPES OF FLOORS 

Like other pavements, concrete floors may be 
either one or two course. If the floors are to be 
subjected to heavy wear, one-course construction 
with hard, tough aggregates is best. In other respects 
concrete floor construction is not unlike that followed 
in building concrete walks, roads, or other concrete 
pavements. In one-course construction a 1:2:3 
mixture is used throughout. In two-course con- 
struction a 1:3:5 concrete is used for the base, while 
the top or wearing course consists of a 1:13^ or 1:2 
mixture. Much of the trouble in two-course work 
comes from not placing the wearing course im- 
mediately after the base is placed. Another cause 
of trouble is that the top coat is usually placed too 
wet. It should be mixed stiff enough so that the 
mixture will have to be scraped from the buckets or 
wheelbarrows. Other objections that have been 



MAKE AND HOW TO USE CONCRETE 63 

advanced against concrete floors have to do with 
their disintegration in some plants where manu- 
facturing solutions of various kinds are spilled on 
them. Concrete floors will not withstand strong 
acids, but such floors are used successfully in dairies, 
creameries, soap factories, salt works, etc. General 
experience seems to prove that inasmuch as dense 
concrete is practically impervious, none of the 
ordinar}^ industrial solutions will injure a concrete 
floor if it is built so that maximum density of con- 
crete is secured. Concrete floors, especially above- 
ground, should be water-tight. The principles of 
water-tight construction have been given else- 
where. They consist merely of properly proportioned 
mixtures placed at the right consistency and proper 
protection of the concrete for several days after the 
work has been finished. 

CONCRETE WALKS 

The principles of concrete floor construction apply 
to concrete walks. Frequently concrete walks are 
made too thin; also, they are frequently laid on 
poorly drained soil, then upheaval, due to freezing of 
water retained beneath the slabs, will mar the 
appearance of the walk, if not destroy it in part. 
Walks, floors, and pavements laid on the ground 
should be on a firmly compacted soil. If drainage is 
not good, a sub-base of clean material well compacted 
may be necessary, but in such cases the sub-base 
must be drained by tile lines, otherwise it will act 
merely as a sump to collect and retain water which 



64 THE RAN SOME BOOK — HOW TO 

will then prove as disastrous as were the whole area 
undrained. 

Specifications for concrete floors, walks, roads, 
streets, and alleys, issued by the Portland Cement 
Association, and obtainable on request without cost, 
go into details of several classes of pavement con- 
struction, so these details will not be given here. 

CONCRETE TANKS 

Concrete is used most successfully in constructing 
many kinds of tanks, employed not only as con- 
tainers for various liquids but as silos, grain bins, 
coal pockets, and similar structures, all of which can 
be regarded as tanks. 

Tanks which are to hold liquids must, of course, 
be water-tight. It is best that concreting on them 
be continuous, to prevent construction seams which 
might cause leakage. Each tank must be rein- 
forced in accordance with its capacity, so that no 
standard rules can be laid down for the quantity or 
spacing of reinforcing material in any such structure. 

Tanks can be either cylindrical or rectangular. 
The same principles of concrete practice apply to the 
small concrete watering trough or tank on the farm 
as apply to the large water storage standpipe or 
reservoir. Properly proportioned mixtures, proper 
consistency, careful spading in forms, and protection 
of the finished work are all vital to success. Small 
watering troughs and tanks, such as used on the 
farm, usually have the inside faces battered or sloped 
so as to relieve pressure from ice if the water should 



MAKE AND HOW TO USE CONCRETE 65 

freeze. Tanks of large capacity carx be built more 
economically if circular in shape than if square or 
rectangular. Less material, both concrete and rein- 
forcing, is required in circular structures than in 
those of other shape of like capacity. Many types of 
silo forms are particularly adapted to the con- 
struction needs of grain bins, water tanks, standpipes, 
and similar concrete structures. 

Reinforcing of tanks must be properly calculated 
and the material must be correctly placed. Pro- 
bably many tank failures have been due to improper 
reinforcing or to the use of unsuitable reinforcing 
materials. For example, old chain, wire rope, and 
similar materials are not suited for tank reinforce- 
ment, as they cannot be accurately placed in the 
forms nor kept in proper position w^hile placing con- 
crete. However strong such reinforcing material 
may be in itself, effectiveness of it is not secured 
when used in reinforced concrete tanks or similar 
structures. For the smaller classes of concrete tanks 
steel rods or mesh fabric m^ay be used, but in large 
grain bins and elevators and similar tanks suitable 
sizes of steel rods and bars must be used. Leaky 
water tanks result from mixtures lean in cement 
or improperly proportioned mixtures, concrete placed 
too dry or too wet, and neglect to protect the con- 
crete from drying out after the work is finished. 



66 THE RAN SOME BOOK — HOW TO 

TYPES OF SILOS 

Concrete is used for silos in the form of monolithic 
construction, concrete block, and cement staves. 
The last two types of construction are essentially 
masonry work. The success of block and stave silos 
depends entirely upon the care used in making and 
laying the particular units. Concrete block and 
cement stave silos are both excellent structures if 
the block and staves have been made according to 
good concrete practice. Block and staves should 
both be steam cured. Concrete silos are a form of 
tank, and to preserve the contents should be made 
water-tight and airtight. This can readily be 
secured by using the proper mixture properly placed. 

Accompanying tables will be found convenient for 
estimating quantities of materials, also as a guide 
for reinforcing silos of various sizes both with mesh 
reinforcing and with rods. 



MAKE AND HOW TO USE CONCRETE 



67 



aVPACITY OF ROUND SILOS IN TONS 



Inside 






INSIDE DIAMETER 


OF 


SILO 






Height 














of Silo 


























in feet. 


10 ft. 


lift. 


12 ft. 


13 ft. 


14 ft. 


15 ft. 


16 ft. 


17 ft. 


18 ft. 


19 ft. 


20 ft. 


22 ft. 


24 


34 


41 


49 


57 


67 


76 


86 


98 


110 


122 






25 


36 


43 


52 


60 


71 


80 


91 


104 


116 


129 


143 




26 


38 


46 


55 


64 


75 


85 


97 


110 


123 


137 


152 




27 


40 


49 


58 


68 


79 


90 


102 


116 


130 


145 


160 




28 


42 


51 


61 


71 


83 


95 


109 


122 


137 


152 


169 


205 


29 


44 


54 


64 


75 


87 


100 


114 


128 


144 


160 


178 ' 216 


30 


47 


56 


67 


79 


91 


105 


119 


135 


151 


168 


187 


226 


31 


49 


59 


70 


83 


96 


110 


125 


141 


158 


176 


196 


237 


32 


51 


62 


74 


86 


100 


115 


131 


148 


166 


184 


205 


248 


33 


53 


65 


77 


90 


105 


121 


137 


155 


174 


192 


215 


260 


34 


56 


68 


80 


94 


109 


126 


143 


162 


181 


200 


224 


271 


35 


58 


70 


84 


98 


114 


132 


149 


169 


189 


209 


234 


282 


36 


61 


73 


87 


102 


118 


136 


155 


176 


196 


218 


243 


293 


37 


63 


76 


90 


106 


123 


142 


161 


183 


204 


227 


252 


305 


38 


66 


79 


94 


110 


128 


148 


167 


190 


212 


236 


262 


316 


39 


68 


82 


97 


115 


133 


154 


173 


197 


220 


245 


272 


328 


40 


70 


85 


101 


119 


138 


160 


180 


204 


228 


255 


282 


340 


41 


72 


88 


105 


124 


143 


166 


187 


211 


236 


262 


291 


352 


42 


74 


91 


109 


128 


148 


172 


193 


218 


244 


270 


300 


363 


43 






113 


133 


154 


179 


201 


225 


252 


280 


310 


375 


44 






117 


137 


159 


184 


207 


233 


261 


289 


320 1 387 


45 










165 


191 


215 


240 


269 


298 


330 1 399 


46 










170 


197 


222 


247 


277 


307 


340 ■ 412 


47 














229 


254 


285 


316 


350 


424 


48 














236 


261 


293 


325 


361 


436 


49 


















301 
310 


334 
344 


371 

382 


449 


50 


















462 























68 



THE RAN SOME BOOK — HOW TO 



TABLE OF DIMENSIONS AND MATERIALS FOR 

ROOFS FOR SILOS WITH DDIMETERS 

8 FEET TO 22 FEET 



Diam- 
eter of 
Silo 


Vertical 
Rise 


Volume 
of Cone, 
in cu.yds 


Cement 
Required 
barrels 


Sand 
Required 
cu. yds. 


Stone 
Required 
cu. yds. 


}4 Inch Reinforcing Rods 


No. of 

Rods 

Required 


Stock 
Length 
of Rods 


No. of 
Lbs. of 
Rods 


10 ft. 
12 ft. 
14 ft. 
16 ft. 

18 ft. 
20 ft. 

22 ft. 


2K ft. 

3 ft. 
3H ft. 

4 ft. 

4 ft. 
4 ft. 
4 ft. 


1.60 
2.20 
2.90 
3.80 

4.50 
5.40 
6.40 


2.80 
3.80 
5.00 
6.60 

7.8 
9.4 
11.1 


.80 
1.10 
1.50 
2.00 

2.60 
2.80 
3.30 


1.20 
1.70 
2.20 
2.90 

3.50 
4.20 
4.90 


31 
33 
45 

87 

93 
107 
113 


12 ft. 
16 ft. 
16 ft. 
10 ft. 

12 ft. 
12 ft. 
14 ft. 


62 

88 
120 
146 

187 
226 
265 



TABLE OF MATEIOALS FOR SILO FOOTING 
AND FLOORS 



Silo 


Cu. 
Yds. 


Footings 


1:2:3 
cu. yds 


Floors 


Footings and 
Floor 


in ft. 


Ce- 
ment 
bbls. 


Sand 
yds. 


Gravel 
yds. 


Ce- 
ment 
bbls. 


Sand 
yds. 


Gravel 
yds. 


Ce- 
ment 
bbls. 


Sand 
yds. 


Gravel 

yds. 


10 
12 
14 
16 

18 
20 
22 


2.44 
2.91 
3.37 
3.84 

4.31 
4.77 
5.24 


2.83 
3.38 
3.91 
4.45 

5.00 
5.53 
6.08 


1.27 
1.51 
1.75 
2.00 

2.24 
2.48 
2.72 


2.10 
2.50 
2.90 
3.30 

3.70 
4.10 
4.51 


.70 
1.07 
1.51 
2.04 

2.64 
3.32 
4.04 


1.22 
1.86 
2.63 
3.55 

4.59 

5.78 


.36 

.56 

.79 

1.06 

1.37 
1.73 


.54 

;82 

1.17 
1.57 

2.03 
2.56 


4.05 
5.24 
6.55 
8.00 

9.59 
11.31 


1.63 
2.07 
2.54 
3.06 

3.61 
4.21 


2.64 
3.32 
4.07 

4.87 

5.73 
6.06 



MAKE AND HOW TO USE CONCRETE 



69 



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MAKE AND HOW TO USE CONCRETE 



73 



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74 



THE RAN SOME BOOK — HOW TO 



TABLE GIVING LINEAL FEET X)F TRIANGLE 
MESH REINFORCEMENT 



Height 
of 




Inside Diameter of Silo 




Silo 


10 feet 


12 feet 


14 feet 


16 feet 


24 feet 


333 Style No. 6 


347 Style No. 6 
40 Style No. 4 


347 Style No. 6 
89 Style No. 4 


336 Style No. 6 
151 Style No. 4 


27 feet 


343 Style No. 6 
34 Style No. 4 


357 Style No. 6 
77 Style No. 4 


357 Style No. 6 
132 Style No. 4 


346 Style No. 6 
204 Style No. 4 


30 feet 


353 Style No. 6 
64 Style No. 4 


367 Style No. 6 
114 Style No. 4 


367 Style No. 6 
178 Style No. 4 


405 Style No. 6 
253 Style No. 4 


33 feet 


363 Style No. 6 
95 Style No. 4 


377 Style No. 6 
150 Style No. 4 


420 Style No. 6 
221 Style No. 4 


468 Style No. 6 
302 Style No. 4 


36 feet 


373 Style No. 6 
125 Style No. 4 


387 Style No. 6 
190 Style No. 4 


476 Stvle No. 6 
264 Style No. 4 


527 Style No. 6 
355 vStyle No. 4 


39 feet 


383 Style No. 6 
159 Style No. 4 


433 Style No. 6 
227 Style No. 4 


529 Style No. 6 
310 Style No. 4 


586 Style No. 6 
404 Style No. 4 


42 feet 


393 Style No. 6 
189 Style No. 4 


483 Style No. 6 
264 Style No. 4 


582 Style No. 6 
353 Style No. 4 


596 Style No. 6 
506 Style No. 4 


45 feet 


434 Style No. 6 
220 Style No. 4 


5.30 Style No. 6 
300 Style No. 4 


638 Style No. 6 
396 Style No. 4 


606 Style No. 6 
604 Style No. 4 


48 feet 


477 Style No. 6 
250 Style No. 4 


570 Style No. 6 
340 Style No. 4 


648 Style No. 6 
485 Style No. 4 


619 Style No. 6 
706 Style No. 4 


51 feet 


518 Style No. 6 
281 Style No. 4 


626 Style No. 6 
377 Style No. 4 


658 Style No. 6 
■ 571 Style No. 4 


629 Style No. 6 
808 Style No. 4 


54 feet 


558 Style No. 6 
314 Style No. 4 


636 Style No. 6 
450 Style No. 4 


668 Style No. 6 
660 Style No. 4 


639 Style No. 6 
906 Style No. 4 


57 feet 


599 Style No. 6 
345 Style No. 4 


646 Style No. 6 
527 Style No. 4 


678 Style No. 6 
746 Style No. 4 


649 Style No. 6 

959 Style No. 4 

53 Style No. 23 


60 feet 


642 Style No. 6 
375 Style No. 4 


656 Style No. 6 
600 Style No. 4 


688 Style No. 6 
835 Style No. 4 


659 Style No. 6 
1008 Style No. 4 
102 Style No. 23 


Floor 


38 Style No. 6 


48 Style No. 6 


68 Style No. 6 


87 Style No. 6 


Roof 


96 Style No. 6 


134 Style No. 6 


182 Style No. 6 


240 Style No. 6 



NoTK. Use 38 in. widths of mesh and lap 2 in. or use 42 in. widths and lap 6 in. 
Reinforcement furnished only in rolls 150 ft., 200 ft. and 300 ft. long. 



MAKE AND HOW TO USE CONCRETE 



TABLE GIVING LINEAL FEET OF TRIANGLE 
MESH REINFORCEMENT 



Height 
of 


Inside Diameter of Silo 


Silo 


18 feet 




j 20 feet 




22 feet 




24 feet 


368 Style No. 
173 Style No. 


6 

4 


337 Style No. 
254 Style No. 


6 
4 


362 Style No. 
279 Style No. 


6 
4 


27 feet 


433 Style No. 
229 Style No. 


6 

4 


409 Style No. 
319 Style No. 


6 
4 


372 Style No. 
419 Style No. 


6 

4 


30 feet 


502 Style No. 
285 Style No. 


6 

4 


484 Style No. 
381 Style No. 


6 

4 


382 Style No. 
558 Style No. 


6 

4 


33 feet 


568 Style No. 
343. Style No. 


6 
4 


556 Style No. 
443 Style No. 


6 
4 


392 Style No. 
698 Style No. 


6 
4 


36 feet 


636 Style No. 
399 Style No. 


6 

4 


566 Style No. 
570 Style No. 


6 
4 


402 Style No. 
837 Style No. 


6 
4 


39 feet 


646 Style No. 
513 Style No. 


6 

4 


576 Style No. 
697 Style No. 


6 
4 


412 Style No. 
977 Style No. 


6 
4 


42 feet 


656 Style No. 
628 Style No. 


6 
4 


586 Style No. 
824 Style No. 


6 

4 


422 Style No. 
1116 Style No. 


6 
4 


45 feet 


666 Style No. 
739 Style No. 


6 

4 


596 Style No. 
951 Style No. 


6 
4 


432 Style No. 
1116 Style No. 
140 Style No. 


6 
4 
23 


4S feet 


676 Style No. 
798 Style No. 
59 Style No. 


6 
4 
23 


606 Style No. 
951 Style No. 
127 Style No. 


6 
4 
23 


442 Style No. 
1116 Style No. 
279 Style No. 


6 . 
4 
23 


51 feet 


686 Style No. 
853 Style No. 
115 Style No. 


6 
4 
23 


619 Style No. 
951 Style No. 
254 Style No. 


6 
4 
23 


452 Style No. 
1116 Style No. 
419 Style No. 


6 
4 
23 


54 feet 


696 Style No. 
909 Style No. 
173 Style No. 


6 
4 
23 


629 Style No. 
951 Style No. 
381 Style No. 


6 
4 
23 


465 Style No. 
1116 Style No. 
558 Style No. 


6 
4 
23 


57 feet 


706 Style No. 
968 Style No. 
229 Style No. 


6 
4 
23 


639 Style No. 
951 Style No. 
508 Style No. 


6 
4 
23 


475 Style No. 
1116 Style No. 
698 Style No. 


6 
4 
23 


60 feet 


716 Style No. 
1023 Style No. 
285 Style No. 


6 
4 
23 


649 Style No. 
951 Style No. 
635 Style No. 


6 
4 
23 


485 Style No. 
1116 Style No. 
837 Style No. 


6 
4 
23 


Floor 


102 Style No. 


6 


125 Style No. 


6 


154 Style No. 


6 


Roof 


300 Style No. 


4 


; 328 Style No. 


4 


400 Style No. 


4 



Note. Use 38 in. widths of mesh and lap 2 in. or use 42 in. widths and lap 6 in. 
Reinforcement furnished only in rolls 150 ft., 200 ft., and 300 ft. long. 



76 THE RAN SOME BOOK — HOW TO 

RECOMMENDED PRACTICE FOR THE CON- 
STRUCTION OF MONOLITHIC CONCRETE SILOS 

The following brief summary of construction 
requirements for monolithic concrete silos will serve 
as a guide for specifications. 

EXCAVATION 

Excavations should be to firm bearing soil always 
below possible frost penetration. Roots, sod, or any 
other perishable material must be removed. Soft, 
spongy spots should be excavated and refilled with 
well-compacted gravel. 

BACK FILLING 

When back filling is necessary it should be done 
after the footings have been completed and have 
thoroughly hardened and the walls have been 
finished to ground line. Provisions for draining the 
silo and for filling and emptying a tank, if such is to 
be built upon the top, should be provided for by in- 
serting the necessary plumbing. Requirements for 
cement and aggregates have been stated elsewhere 
and these apply to silo construction. Quality of re- 
inforcement has also been described in another 
section. Wire mesh may be used instead of rods but 
should be equal in cross-sectional area to the rods for 
which substituted. It should be lapped not less than 
four inches on vertical laps and not less than eighteen 
inches on horizontal laps, all laps being securely 
wired together. 



MAKE AND HOW TO USE CONCRETE 77 

FORMS AND FOOTINGS 

All silos are now usually built by using some one 
of the several excellent commercial forms now on the 
market. Wall footings should be of such width that 
pressure on the soil will not exceed 3,000 pounds per 
square foot. For silos not over 40 feet high a footing 
1 foot thick and 2 feet wide will usually be sufficient. 

MIXTURES 

Wall footings should be a 1:3:5 mixture. Walls 
proper should be a 1 : 23/^ : 4. Roofs, floors, and walls, 
and floors of tanks should be a 1:2:3 mixture. A 
quaky consistency is best. 

PLACING CONCRETE AND STEEL 
REINFORCEMENT 

If steel rods are used the verticals should be 
embedded not less than one foot in the concrete 
footings. If wire mesh is used, the lower six inches 
of the first layer and the lower one foot of the ver- 
ticals should be embedded in the concrete footings. 
Concrete should be well spaded next to the forms to 
secure a smooth surface. Walls should be uniformly 
six inches thick. Reinforcing should be placed mid- 
way between inner and outer surfaces of the wall and 
thoroughly embedded. At doorway openings the 
horizontal bars, or if mesh is used, the horizontal 
wires, should be bent around vertical bars alongside 
the doorways. 

It is best that concreting of silos be continuous, 
but frequently this is not practicable. ^Mien neces- 
sary to discontinue work on the walls, as at night, 



78 THE RAN SOME BOOK — HOW TO 

the concrete should be left rough so that a good bond 
may be easily secured between fresh concrete and 
that previously placed. Sometimes a strip of sheet 
steel or galvanized iron is partly embedded in the 
concrete, and when concreting is resumed this as 
well as the surface of the old concrete is well washed, 
then painted with a cement grout paint before 
concreting is continued. 

When a tank is to rest on top of the silo walls the 
first section of the tank wall should be placed at the 
same time as the floor, so as to prevent a leak at the 
point where the tank starts. Care should be taken 
not to remove forms from beneath the tank floor 
slab until all possibility of collapse has passed. 
Each tank of this kind is a subject of special design 
depending upon the capacity. 

If concreting is done in warm weather the concrete 
should be protected while hardening by frequent 
sprinkling or by some protective covering that will 
prevent rapid drying. If the work is done in cold 
weather protection should be given to prevent 
injury to the concrete from freezing, according to 
methods described elsewhere. 

ROOFS 

Many concrete buildings fall short of what they 
should be. They are finished with some kind of a 
roof other than concrete. Flat roofs are the simplest 
type of concrete roofs to build. They are par- 
ticularly suited to small farm buildings and other 
small structures. 



MAKE AND HOW TO USE CONCRETE 79 

Concrete roofs must be properly designed. To a 
certain extent tables can be used for slabs of various 
thicknesses and span where only small buildings are 
involved. For larger buildings, involving greater 
spans, roofs must be designed for the particular 
structure. 

The following table shows thickness of slab re- 
quired for concrete roofs or roof slabs of various 
dimensions from four feet square up to sixteen feet 
square : 



TABLE I 
THICKNESS OF ROOF SLABS IN INCHES 



Width in Ft. 
between 


Length of Roof in Feet between Center Lines of Walls 


of Walls 


4 ft. 


6 ft.. 1 8 ft. 


10 ft. 


12 ft. 


14 ft. 


16 ft. 


4 feet 
6 feet 
8 feet 


2 in. 


2 in. 

2Kin. 


23^ in. 
2Hin. 
3 in. 


23^ in. 
23^ in. 

33^ in. 
33^ in. 


23^ in. 

3 in. 
31^ in. 

4 in. 
4 in. 


23^ in. 
3 in. 
33^ in. 
43^ in. 
4Kin. 
5 in. 


2J^in. 

3 in. 

4 in. 


10 feet 




43/^ in. 


12 feet 




5 in. 


14 feet 




53^ in. 


16 feet 






6 in. 









Load = weight of roof + 50 pounds per square foot. 



80 



THE RAN SOME BOOK — HOW TO 



The following table shows the amount of cement, 
sand, and pebbles or broken stone required for roofs 
of various area and thickness: 



TABLE II 
CEMENT, SAND, AND STONE OR PEBBLES 

Required for Concrete Slab Roofs. Proportions for concrete 
1:2:3. Each cubic yard of 1:2:3 concrete requires about 1.74 
barrels of cement, .52 cubic yards of sand, and .77 cubic yards of 
stone. 





WIDTH OF SLAB IN 


FEET 


(BETWEEN 


EAVES) 








4 


6 


8 


10 


12 


14 


16 


^ 


9 S 

o 1 

1! 
^1 


4 
6 
8 
10 
12 
14 
16 


0.7 
1.0 
1.7 
2.2 
2.6 
3.0 
3.5 


2.0 












s- 












^> ^ 


2.6 
3.3 
4.7 
5.5 
6.2 


4.2 
6.1 
7.3 
8.5 
10.1 










O -1 
o 11 


7.6 
10.4 
13.7 
14.4 








12.5 
16.4 

20.8 






1 1 


21.2 
26.7 


'33.'3' 


•o 


li 

o ^ 

^1 


4 
6 
8 
10 
12 
14 
16 


1.4 
2.1 
3.4 
4.3 
5.2 
6.1 
6.9 














% 


3.9 
5.2 
6.5 
9.4 
10.9 
12.5 












2 


8.3 
12.1 
14.6 
17.0 
20.2 










1 


15.2 
20.8 
27.3 

28.8 








25.0 

32.8 
41.6 






3 

o 


42.5 
53.4 


m.Q 




.s s 

1 1 
^ 1 


4 
6 
8 
10 
12 
14 
16 


2.1 
3.1 
5.1 
6.5 
7.8 
9.1 
10.4 














c 


5.9 

7.8 
9.8 
14.0 
16.4 

18.7 












12.5 

18.2 
21.8 
25.5 
30.3 










"3 1 


22.7 
31.2 
41.0 
43.2 








1 ^ 


37.4 
49.1 
62.4 






3 


63.7 
80.1 


"99'8" 



MAKE AND HOW TO USE CONCRETE 



81 



The following table shows the size and spacing of 
reinforcing rods for roof slabs of various dimensions : 

TABLE III 
SPACING OF REINFORCING RODS IN INCHES 



width in Ft, 
between 

Center Lines 
ol Walls 



Length of Roof in Feet between Center Lines of Walls 



4 ft. 



6 ft. 



8 ft. 



10 ft. 



12 ft. 



14 ft. 



16 ft. 



Size 
Steel 



4 feet. . 
6 feet. . 
8 feet. . 

10 feet.. 
12 feet.. 
14 feet.. 

16 feet. . 



12 in.. 
12 in. 



9iin. 
24.in. 

6 in. 
6 in. 



Sin. 
36 in. 

4f in. 
12 in. 



36 in. 



4 in. 
36 in. 



Sin. 
36 in. 



4 in. 
36 in. 



Sin. 
36 in. 



4 in. 
36 in. 



Sin. 
36 in. 

4 in. 
36 in. 



11 in. 
11 in. 



9| in. 
22 in. 

8f in. 
8f in. 



. NOTE— U p p e r 
figures are for cross 
reinf or cement; 

■ lower figures for 

■ long reinforcement 



36 in. 

7f in. 
16 in. 
6|in. 
6i in. 



7f in. 
36 in. 

7 in. 
27 in. 
5f in. 
12 in. 

5Jin. 
5j in. 



7| in. 
36 in. 



36 in. 
51 in. 
16 in. 



4 in. 
4 in. 



Load = weight of roof + 50 pounds per square foot. 



The following, example shows method of using the 
three tables preceding : 

Example. Required, the thickness of slab, 
amount of concreting materials, spgicing of lateral 
and transverse reinforcement, and the amount of 
reinforcing rods, for the flat slab roof of a building 12 



82 THE RANSOME BOOK — HOW TO 

feet by 14 feet in outside dimensions, with 12 inch 
eaves on all sides. The size of the roof slab between 
the center lines of walls will be 13 feet 6 inches by 
11 feet 6 inches. Referring to Table I, we run down 
the vertical column at the left to the smaller dimen- 
sion of the slab, which in this case is 11 feet 6 inches. 
As this dimension is not given in the table we take 
the next larger, which is 12 feet. Running across 
horizontally to the larger dimension of the slab 
(13 feet 6 inches) we find that this is not given in 
the table, but that we must take 14 feet. In the 
square directly below 14 feet, and horizontally 
opposite 12 feet, we find the required thickness of 
the roof to be 43^ inches. By reference to Table II 
the quantities of materials required are easily 
obtained. The size of the roof over the eaves is 14 
feet by 16 feet. The table is divided into three 
parts showing respectively the amounts of cement, 
sand, and pebbles required for roofs of various sizes. 
The upper portion of the table gives the number of 
sacks of cement required and those below it give the 
number of cubic feet of sand and pebbles or stone 
necessary. By referring to the table we find that the 
roof will require about 25 sacks of cement, 53 cubic 
feet of sand, and 79 cubic feet of pebbles or stone. 

The spacing of the reinforcing rods is shown in 
Table III. As the roof is 11 feet 6 inches by 13 feet 6 
inches between center lines of walls, the next larger 
dimension shown in the table should be used. These 
are 12 feet by 14 feet. By running down the left 
hand vertical column to 12 feet, then running across 



MAKE AND HOW TO USE CONCRETE 83 

horizontally to the 14 foot column, we find that cross 
reinforcement (running parallel to the short sides of 
the house) should be 5% inches apart, and the 
longitudinal rods (running the long way of the house) 
12 inches apart. Round or square | inch rods should 
be used, as shown in the column to the right of the 
table. The roof being 16 feet long and 14 feet wide, 
over eaves, will require thirty-four f inch rods 14 
feet long, parallel to the short sides, and seventeen 
I inch rods 16 feet long, parallel to the long side. 

Note. The foregoing data and tables are taken from ''Small 
Farm Buildings of Concrete," issued by the Universal Portland 
Cement Company, to whom acknowledgment is hereby made. 

FIELD PRACTICE IN CONCRETE PAVEMENT 
CONSTRUCTION 

SPECIFICATIONS 

The history of concrete pavements in the United 
States dates from 1894, in which year several blocks 
were paved with concrete in the city of Bellefon- 
taine, Ohio. For a number of years thereafter this 
pioneer work attracted no particular attention, nor 
was any considerable progress made in the use of 
concrete as a pavement for roads, streets, or alleys. 
Within the past three or four years the yardage has 
increased by leaps and bounds until, on the first of 
January, 1918, there were between 8,000 and 9,000 
miles of concrete roads, streets, and alleys in the 
United States. 

In the past three or four years also there has been 
marked progress in standardizing methods of con- 



84 THE RAN HOME BOOK — HOW TO 

Crete pavement construction. The best practice 
has perhaps been brought to Hght as a result of two 
National Conferences on Concrete Road Building, 
combined with concerted work on the part of the 
American Concrete Institute, the American Society 
for Testing Materials, and the Portland Cement 
Association. As a result there are standard specifica- 
tions for concrete roads, streets, and alleys that 
embody practice based on extensive experience, 
which if followed is certain to insure that the result- 
ing pavement will have no superior, if an equal. 
The latest of these specifications are those adopted 
by the American Concrete Institute in 1917, which 
can be obtained from the Portland Cement Associa- 
tion, 111 West Washington Street, Chicago, free of 
charge. They should be used as a basis for any 
other specifications covering the class of concrete 
work to which they apply. 

TYPES OF CONCRETE PAVEMENTS 

In general there are but two types of concrete 
pavements — one-course and two-course. The first 
consists of one mixture of concrete — a relatively 
rich one, such as a 1:2:3 — laid at one operation to 
the required thickness on the prepared roadbed or 
subgrade. 

The second consists of a base and wearing course, 
the first of a leaner mixture on which is laid im- 
mediately after the base has been placed and before 
it has commenced to harden, a top or wearing course 
of a rich mixture. Where suitable materials are 



MAKE AND HOW TO USE CONCRETE 85 

obtainable either on the site of the work or con- 
venient to it, one-course construction is to be pre- 
ferred. As a rule, two-course construction is used 
only where local materials lack sufficient toughness 
and wear resistance to withstand the impact or 
abrasion of traffic. Then the local materials are 
used in the less important base and the relatively 
small amount of higher grade materials necessary 
for the top or wearing course are shipped in. 

OBJECT OF SPECIFICATIONS 

Specifications for any work go into the details of 
the various materials to be used and the methods of 
using them. Concrete for concrete pavements, such 
as roads, streets, and alleys, like concrete for any 
other work, is composed of Portland cement, aggre- 
gates, and water. The volume of cement required 
in the construction of concrete roads represents about 
one sixth of the total of the materials used. Port- 
land cement is subject to rigid specifications, and 
while specifications for concrete roads, streets, and 
alleys require that tests of sand and stone be made 
of those materials when used in pavement work, 
rarely is the attention given to these important 
materials that should be required. The mistaken 
impression is too generally prevalent that any sand 
or stone mixed with Portland cement will make good 
concrete. Without fear of contradiction it may be 
said that the majority of unsatisfactory concrete 
paving jobs are due to the use of inferior aggre- 
gates; and much of the inferiority may be found 



86 THE RAN SOME BOOK — HOW TO 

in the sand. Since the strength of concrete depends 
entirely upon the character of the materials used, it 
is highly important that the sand be composed of 
hard grains. When it is of grains of uniform size, 
more cement is required to obtain the same strength 
than where the grains range in size from the finest 
permissible to 34 inch. The sand should not contain 
vegetable matter or other similar impurities, as the 
presence of such results in defective bond between 
cement and aggregates and consequently in weak 
concrete. Vegetable matter, if present, may through 
chemical action prevent the setting of the cement. 
Road contractors should not only welcome tests 
upon sand made by the engineer, but should be pre- 
pared to make them on their own account. They 
effect a direct saving in the end. 

COLORIMETRIC TEST FOR ORGANIC IMPURITIES 
IN SAND 
Until recently there were no simple, reliable tests 
that could quickly be made by the contractor. 
Within the past year, however, there has been 
developed by Duff A. Abrams, Professor in Charge 
of the Structural Materials Research Laboratory, 
Lewis Institute, and Oscar E. Harder, Chemist, 
Structural Materials Research Laboratory, a simple 
method for detecting organic impurities in sand. A 
simple colorimetric test may be used for detecting 
the presence of organic impurities of a humous or 
vegetable nature in sand. This test was fully de- 
scribed in a bulletin entitled '' Colorimetric Tests for 



MAKE AND HOW TO USE CONCRETE 87 

Organic Impurities in Sand" that was issued by the 
Structural Materials Research Laboratory in 1917. 
Copies of this pubUcation can be obtained from the 
Portland Cement Association. But the simple 
application of these tests to field practice differs 
slightly from the method applied in the laboratory, 
principally in that comparisons are made with 
definite color standards. 

METHOD FOR FIELD TEST 

The field test consists of shaking the sand 
thoroughly in a dilute solution of sodium hydroxide 
(NaOH) and observing the resultant color after the 
mixture has been allowed to stand for a few hours. 
Fill a 12-ounce graduated prescription bottle to the 
43/^-ounce mark with the sand to be tested. Add a 3 
per cent solution of sodium hydroxide until the 
volume of the sand and solution, after shaking, 
amounts to 7 ounces. Shake thoroughly and let 
stand for twenty-four hours. Observe the color of 
the clear liquid above the sand. A good idea of the 
quality of the sand can be formed earlier than 
twenty-four hours, although this period is believed 
to give best results. 

If the solution resulting from this treatment is 
colorless or has a light-yellowish color the sand may 
be considered satisfactory in so far as organic im- 
purities are concerned. On the other hand, if a dark- 
colored solution of a color deeper than that indicated 
by Plate 2 is produced the sand should not be used 
in high-grade work such as is required in roads and 



88 THE RAN SOME BOOK — H OW TO 

pavements or in building construction. Sands show- 
ing color as dark as Plate 3 may be used in unim- 
portant concrete work. Sands showing colors darker 
than Plate 3 should never be used for concrete. 
Plate 5 represents the color of the solution obtained 
with an unusually dirty sand or from a sample of soil 
high in loam. A small quantity of material of this 
kind would make a sand unsuitable for use in concrete. 
While it is not practicable to give exact values for 
the reduction in strength corresponding to the 
different colors of solution, the tests made thus far 
show this relation to be about as follows: 



Color Plate Number 


Reduction in Compressive Strength of 

1:3 Mortar at Seven and Twenty-eight Days 

Per Cent 


1 

2 
3 

4 
5 


None 
10- 20 
15- 30 
25- 50 
50-100 



Washing sands has the effect of greatly reducing 
the quantity of organic impurities present. How- 
ever, even after washing, sands should be examined in 
order to determine whether the organic impurities 
have been reduced to harmless proportions. 

APPARATUS 

The following list includes sufficient apparatus for 
making five field tests at a time : 

Five 12-ounce graduated prescription bottles. 
Stock of 3 per cent solution of sodium hydroxide (dissolve 1 
ounce of sodium hydroxide in enough water to make 32 ounces). 



MAKE AND HOW TO USE CONCRETE 89 

This material can be purchased at most drug stores 
at a cost of about one dollar. 



SUMMARY 

Experience and tests have shown that it is the 
presence of organic impurities of a humous nature 
that is responsible for most defective sands. The 
colorimetric test furnishes a simple and inexpensive 
method for detecting the presence of such im^purities. 
The test made in the manner described above will 
be found useful for : 

(1) Prospecting for sand supplies. 

(2) Checking the cleanness of sand received on the job. 

(3) Preliminary examination of sands in the laboratory. 

This test is now being used by a large number of 
testing laboratories, engineers, and contractors in 
passing on the suitability of sands for use in concrete. 

In certain instances the test has been made the 
basis of specification requirement for sand. 

It is much easier to detect unclean stone or gravel 
than it is to detect unclean sand. The colorimetric 
tests for sand will, however, reveal cleanliness or the 
reverse with accuracy. 

TESTING COARSE AGGREGATES 

Stone or pebbles used as coarse aggregate also 
should be subjected to careful inspection and test. 
Coarse aggregate is required to successfully with- 



90 THE RAN SOME BOOK — HOW TO 

stand the abrasive action and impact imposed by 
traffic. Soft stone or stone containing soft particles 
will not stand up under heavy traffic. Flat stones in 
the surface of a road do not have sufficient embed- 
ment. They are easily broken or torn out by traffic, 
thus leaving a pothole. Where the dimensions of 
stone exceed \}/2 inches it is sometimes difficult to 
obtain an even surface and more work is required 
with the template when striking off to the desired 
contour. A graded stone with particles ranging 
from coarse to fine is economical if mortar required 
to obtain a strength equal to that of stone not so 
graded is used. Where aggregates are dirty, but 
suitable in other respects, arrangements should be 
made to wash them before using in the concrete 
mixtures. Specification requirements prohibit the 
use of crusher-run stone, bank-run gravel, or 
artificially prepared mixtures of coarse and fine 
aggregate. 



PROPORTIONING 

All materials entering into concrete should be 
accurately proportioned. Successful concrete pave- 
ment work requires uniformity of mixture which 
cannot be obtained with bank-run gravel or crusher- 
run stone. In most gravel pits the sand exceeds the 
pebbles or broken stone by twice. Concrete 
mixtures in which such aggregate is used produce 
weak concrete due to excess mortar. A road surface 
showing neat cement at one point, mortar at 



MAKE AND HOW TO USE CONCRETE 91 

another and aggregate at another will not wear 
evenly. Screening and separating fine and coarse 
aggregates and reproportioning them in correct 
volumes results in economy in the use of cement. 



MIXING WATER 

Mixing water must be clean, free from oil, acid, 
alkali, or vegetable matter. A large quantity of 
water is required in concrete road construction. It 
has to be used, first, for wetting down the subgrade, 
during rolling, again wetting it prior to placing con- 
crete; also to supply the boiler of the mixer and to 
make the concrete mixture itself, and finally must be 
used for sprinkling or ponding after the concrete has 
been placed and finished to insure proper hardening. 
Before submitting a bid for concrete road w^ork the 
contractor should thoroughly investigate the source 
of water supply. The water equipment requires a 
two-inch pipe of sufficient length to reach at least 
half way between the source of supply. It should 
have a capacity of at least fifty gallons per minute. 
To avert excess expense occasioned by delay from 
irregular water supply, the contractor should have 
an additional pump so that if one breaks down the 
other can immediately be put in commission. The 
pipe line should be laid with hose connections about 
every two hundred feet. A blow-off valve or com- 
pensating tank should be placed on the high point 
of the line to prevent bursting when the pump is 
working and no water is being used. 



92 THE RAN SOME BOOK — HOW TO 

GRADING 

Before concrete for pavements can be laid there 
must be a properly prepared roadbed or subgrade. 
It has been proved that many of the cracks which 
develop in concrete pavement are due to settlement, 
poor drainage, or other unstable conditions of the 
roadbed or subgrade, so that too much care cannot 
be taken to properly prepare the surface on which 
concrete is to be laid. Fills must be allowed to 
finish all settlement before placing concrete. They 
should also be made by placing the material in layers 
of uniform thickness and rolling compactly with a 
ten-ton or heavier roller until reduced to the utmost 
compactness. 

DRAINAGE 

It is well known that stability of railroad roadbeds 
depends more largely upon good drainage than any 
other one fundamental of construction. Drainage is 
equally important in construction of the subgrade 
or roadbed for concrete pavement. If the foundation 
on which the slabs rest is not thoroughly drained so 
that no water will be retained beneath the slabs, 
then it is certain that there will be heaving and 
consequent cracking of the concrete due to freezing 
and expansion of the retained water. Drainage of 
the surface of concrete roads and streets is provided 
for by crowning the surface, this being done by 
striking off with a template cut to the required 
contour. Alley pavements are usually dished, that 
is, are lower in the center than at the sides, or have, 



MAKE AND HOW TO USE CONCRETE 93 

as is said, an inverted crown. In this way the surface 
drains quickly, while the pavement serves also the 
purpose of a gutter. 

HANDLING MATERIALS ON THE JOB 

Cement is shipped in paper bags and cloth sacks. 
The cost of the packages is included in the price of 
cement. The cloth sacks will be redeemed by the 
manufacturer if returned in good condition. There- 
fore it is necessary that workmen be properly in- 
structed as to care of sacks out on the job. By 
permitting workmen to carelessly or purposely 
destroy or damage sacks by cutting them with a 
knife or shovel, or by allowing them to use sacks for 
knee pads, aprons, etc., a loss is incurred of ten 
cents or more for every sack so used. On large jobs 
proper care of sacks warrants assigning one or more 
men to have entire charge of shaking and bundling 
them properly for shipment. Cement is purposely 
made sensitive to moisture. It therefore must be 
so stored before use that it cannot be injured by 
dampness. A tight building with a tight floor raised 
sufficiently above ground so that free circulation of 
air can take place around the piles is necessary. On 
the job there should never be more than one day's 
supply piled along the work, and it should never be 
piled on the ground, but on board platforms, so that 
in case of a sudden shower it can be quickly covered 
with tarpaulins and thus protected against injury. 
Aggregates are usually distributed in piles along the 
subgrade, sand on one side, crushed stone cr pebbles 



94 



THE RANSOME BOOK — HOW TO 



on the other. An accompanying table shows the 
quantities of materials required for a concrete pave- 
ment of the width and thickness indicated and will 
be found convenient when estimating quantities of 
aggregates to be distributed along the work. 

QUANTITIES OF MATERIALS REQUIRED FOR 

LINEAR FOOT OF CONCRETE PAVING FOR 

THE WIDTHS AND THICKNESSES AT 

SIDES AND CENTER AS SHOWN 







CEMENT 


SAND 


Rock or 


PEBBLE.S 


Width 


Side and 
Center 


(bbls.) 


(cubic yards) 


(cubic 


yard.s) 


(feet) 
















(inches) 


1:2:3 


1:1H:3 


1:2:3 


1:1J^:3 


1:2:3 


1:13^: 3 


9 


6-7 


0.32 


0.35 


0.10 


0.08 


0.14 


0.16 


16 


6-8 


0.63 


0.68 


0.19 


0.15 


0.28 


0.30 


18 


6-8 


0.71 


0.77 


0.21 


0.17 


0.32 


0.34 


20 


6-8H 


0.82 


0.90 


0.24 


0.20 


0.36 


0.40 


24 


6-9 


1.01 


1.10 


0.30 


0.24 


0.45 


0.49 



Quantities based on the assumption of 45% voids in the coarse 
aggregate. 



To prevent possibility of dirt or refuse becoming 
mixed with the aggregates, some contractors have a 
supply of planks to lay on the roadbed so that 
aggregates can be dumped upon them. Frequently 
planks are laid on the roadbed or subgrade to enable 
loaded wagons being driven along without cutting 
up the subgrade. In handling broken stone which 
is dumped directly on the ground ballast forks should 
be used to prevent dirt being shoveled up w^ith the 
aggregate. Care should also be taken when shoveling 



MAKE AND HOW TO USE CONCRETE 95 

sand from the piles that they are not thoroughly 
cleaned up, because to do so would cause dirt to be 
shoveled up also. 

JOINTS 

Joints are placed in concrete pavements to pro- 
vide for volume changes in the concrete owing to 
variations in moisture content and in temperature. 
Engineers are not in thorough accord as to the dis- 
tance which such joints should be spaced from each 
other. Some are disposed to omit a made joint 
entirely, knowing that the concrete will eventually 
crack, due to contraction at certain intervals, thus 
providing such ^^ joints" as are needed. However, 
these are not straight across the pavement, therefore 
are unsightly and are also more difficult to keep in 
good repair because of their irregular edges. For 
this reason a made joint is preferable. Engineers 
are also not in accord as to whether joints should be 
protected or unprotected; that is, whether there 
should be placed in the concrete at each end of 
every slab a metal protection plate with joint filler 
material between or whether the plate should be 
omitted and merely a prepared joint filler used. 
In general, joints should not exceed J<4 or ^^ of an 
inch in width. Wider joints are likely to suffer 
increased wear due to impact of steel-tired wheels 
crossing them. The strips of fiber matrix and 
bitumen used for joint filler come in convenient form. 
They are easy and economical to handle and are 
shipped the required thickness. They are also easy to 



96 THE RAN SOME BOOK — HOW TO 

install, contain sufficient bitumen to seal the surface 
and protect the edges of the concrete, and there is no 
pulling of templates, all of which makes for economy 
and warrants the adoption of this type of joint 
filler. When metal protection plates are used, care 
should be taken in placing the installation device, 
the plates and the filler cut to the proper crown. 
When the unprotected joint is used the filler should 
be allowed to extend about }/2 inch above the 
finished pavement surface so that traffic will iron it 
out and thus help to more completely seal the joint. 
Steel protection plates are set in place by an in- 
stalling device. These differ somewhat for the 
different types of plates. In some cases they may 
be used as a template to test the correctness of the 
pavement crown. Where plates are used it is very 
necessary that they be carefully set and that the 
pairs be of the same curvature. If they are not, the 
joints will be low or high or in some respect uneven, 
owing to the inequalities in the plates forming the 
pair. 

PLACING CONCRETE 
Before concrete is placed on the prepared sub- 
grade, the foundation should be well sprinkled to 
prevent the soil from absorbing water from the 
concrete mixture. Concrete paving mixers are 
equipped either with a chute or with boom and 
bucket for depositing the concrete. Either type 
properly used will give satisfactory results, but where 
a mixer with chute is used care must be taken not to 
attempt to distribute concrete over such an area that 



MAKE AND HOW TO USE CONCRETE 97 

it is necessary to have the chute he at a flat angle, 
thus tempting the contractor to use too wet a con- 
crete so that the mixture will flow down the chute 
readily and into place. This objection is not com- 
mon to types of mixers having the drum mounted so 
high that the chute never need lie at an angle less 
than twenty- two to twenty-five degrees. 

In planning paving work the greatest progress will 
be made if things are so arranged that the mixer can 
travel up grade. This allows laborers to wheel 
materials downhill to the mixer and also helps the 
finishers, as any excess water from the concrete will 
run away from them onto portions of the pavement 
that have hardened. If the mixer is working down 
grade, materials must be hauled uphill to it, and 
this makes harder work, not to mention more un- 
satisfactory conditions for finishing. Contractors 
should know in advance of commencing work the 
exact lines and grades upon which they are to work. 
Such information can be obtained only from the 
engineer's grade stakes which designate the outline 
of the proposed pavement. These are set as a 
convenience to the contractor as well as a guide to 
the engineer when checking up the work while under 
construction. Stakes are often accidentally destroyed 
or obliterated, but they should be carefully replaced. 

HANDLING EXCESS MATERIAL 

Rather than haul away all excess material it is 
economical to leave sufficient at the roadside to cover 
the surface cf the concrete with at least two inches of 



98 THE RAN SOME BOOK — HOW TO 

earth for protection while curing, unless provisions 
can be made and water is available in required 
quantity to adopt the ponding method of curing. 
If excess material in quantities sufficient to use as 
protection for the finished work is not left along the 
roadside it becomes necessary to rehandle the re- 
quired amount of earth covering. Such material 
can be hauled away more readily and economically 
after the road has been open to traffic, as the highway 
is then paved. 

FINISHING CUTS AND FILLS 

There is a tendency upon the part of the laborers 
to leave slopes of embankments concave and those of 
cuts convex. It is more economical to construct 
slopes properly at first than to go back and attempt 
to make adjustments to work not properly done in 
the first instance. The final dressing of slopes should 
be commenced in sufficient time so that slopes and 
shoulders can be completed simultaneously. 

SHOULDERS 

Shoulder material should be such as to permit of 
compacting by light roller only. The material 
should be self-draining and should possess sufficient 
stability to prevent rutting. The practice has been 
adopted in many places of making earth shoulders 
and seeding them to grass. The resulting sod makes 
not only an attractive shoulder but one that can 
hardly be washed out. Of course this is not practi- 
cable on narrow concrete pavements, since then 



MAKE AND HOW TO USE CONCRETE 99 

shoulders must be of a material that will stand up 
when passing traffic turns off the pavement and onto 
the shoulder. An old bituminous macadam road 
makes good shoulder material. Gravel or stone 
containing some clay also makes good shoulders. 

The common tendency today is to build wider 
concrete pavements. The minimum should be 
eighteen feet, because vehicles are larger and the 
wider road permits traffic to pass safely without 
reducing speed. 

FORMS 

Wherever the stretch of concrete pavement to be 
built is a mile or more in length it is economy to use 
as side forms a stiff steel channel. There are several 
types manufactured for the purpose. If wood forms 
are used they will render longer service if capped 
with angle irons. This also stift^ens them and allows 
the template to be worked easily along their tops. 
A warped wooden form is difficult to stake to line 
and grade, and therefore increases the labor cost 
and results in a wavy road. The forms must be the 
same depth as the concrete at the edges. If too deep, 
extra work is required in digging a trench to set 
them. If not deep enough they must be blocked up 
at an increased cost, and as the easiest method of 
doing this is to use stones, mortar runs from the 
concrete under the forms and is wasted. Man}^ 
forms are not properly constructed. Frequently, too, 
the joints in forms on opposite sides of the road are 
placed directly opposite each other instead of being 
staggered, as are the joints of rails on the railroad. 



100 



THE RANSOM E BOOK — HOW TO 



Of the accompanying sketches, the upper shows 
the method of supporting side forms to grade, which 
is easily apphed. It will be noticed that 2 by 2 inch 




^ 
U 









CZT 



U.- 



Fig 2 



fi 



v^ o/7g/e /ron 



V-s-^ 



^==^ 



h*'i. 



Fig 3 



r 



K 



Wood form notched 
OS shown 



wood stakes about 12 inches long are driven along 
the line of the side forms to the elevation of the 
bottom of the form. These stakes of course are 
intended merely to support the side form to the 
proper elevation, other stakes being driven in the 
regular way for the purpose of holding the forms in 



MAKE AND HOW TO USE CONCRETE 101 

line. It will be seen also that the joints in the side 
forms are staggered to prevent a wave being formed 
across the road in case form joints are low. 

The next sketch shows details of wood side form 
construction. The angle iron cap shown extends six 
inches beyond the end of the form to insure that 
adjacent forms are maintained at the same eleva- 
tion. A slight modification of this is shown in the 
next sketch. This method will prevent bending of 
angles if forms are handled roughly. Proper placing 
of side forms involves a little more expense than the 
careless placing that is altogether too commonly 
practised. The improved riding quality of the road 
and the increased satisfaction resulting therefrom 
compensate for the slightly added trouble and 
expense of setting forms properly. When concrete 
is placed against the forms they tend to bulge out- 
ward. Unless properly staked to prevent this bulge, 
more concrete is placed than is required and the 
contractor thus furnishes material for which he is 
not paid. To stake wooden forms, ^ io ^^ inch 
round steel pins have proved more satisfactory than 
wood stakes. They should be 12 to 18 inches long. 
In all cases the pins or stakes must be driven below 
the top of the forms, otherwise the tops will act as 
obstacles to working the template. 

MIXING CONCRETE 

No other single operation of concrete pavement 
work is more often slighted than mixing of the 
concrete. Attempt to speed up the work often 



102 THE RAN SOME BOOK — HOW TO 

results in shortening the time of mixing. Today 
the tendency is to increase time of mixing, since it 
has been proved that up to a certain hmit, other 
things being equal, longer mixing has great influence 
on the strength, wearing qualities, and other de- 
sirable properties of the concrete. Some mixer 
manufacturers make extravagant claims that owing 
to the particular construction of their machine its 
efficiency is greater than others and therefore con- 
crete need be mixed only for a very short time. 

The method of measuring materials, including 
water, must be one which will insure separate and 
uniform proportions of each material at all times. 
A bag of Portland cement, ninety-four pounds net, 
is considered as one cubic foot. Measuring the 
cement is therefore a simple and economical pro- 
cedure. Under most conditions the easiest and 
cheapest method of measuring the sand and stone is 
by wheelbarrows. Those commonly in use have a 
definite capacity but require a certain amount of 
heaping to produce it. If wheelbarrows are used 
they should be of the type intended for that purpose 
and have a known, definite capacity when properly • 
struck off level full, as gaging the heaping by the eye 
often results in variable quantities of material being 
used in the different batches. Unless wheelbarrows 
of definite capacity when struck off level are used a 
bottomless measuring box of the desired capacity 
should be used by setting into an ordinary wheel- 
barrow, filling evenly, and then be struck off. When 
the job is large enough to warrant, industrial railway 



MAKE AND HOW TO USE CONCRETE 103 

cars can be loaded with exact amounts at the stock 
pile or quarry. The carload is dumped directly into 
the hopper of the mixer. Materials must never be 
measured by the shovelful. No two men will load a 
shovel alike. The amount of water required may 
vary from day to day, depending on the varying 
moisture content of the aggregates. The amount of 
water giving the desired consistency should be 
noted each day when beginning work and this 
amount be adhered to as long as the aggregates 
remain in the same condition. The latest improved 
paving mixers have adjustable tanks for measuring 
the water, and this is the most satisfactory and 
economical method. 

QUANTITY OF WATER 

A certain quantity of water is necessary for the 
chemical reaction of the cement. A certain addi- 
tional quantity is generally required to produce a 
plastic mass which can be molded in the desired 
form. Tests have shown that the effect of propor- 
tional changes in the mixing water is approximately 
the same for all mixes of concrete. The amount of 
water which gives the maximum strength in con- 
crete produces a mix which in general is too stiff for 
most purposes. The exact amount of water cor- 
responding to the maximum strength of concrete will 
vary with the method of handling and placing the 
concrete. Any method which involves puddling, 
tamping, rolling, or vibration, or the exertion of 
pressure in any manner, will have a tendency to in- 



104 



THE RAN SOME BOOK — HOW TO 



crease the strength of the concrete regardless of the 
amount of water used. How this influence is dis- 
played in the strength of concrete pavements will be 
referred to later when describing finishing methods. 
In constructing concrete roads it is necessary to 
mix the concrete a little wetter than that giving the 
maximum strength. The consistency which should 
be aimed at in constructing roads corresponds to 
about 105 to 115 per cent of that giving the maximum 
strength. In other words, a small portion of the 
strength must be sacrificed in order to secure a work- 
able concrete. It is evident that there may be a 
difference of opinion as to what constitutes a work- 
able mix, but the accompanying table will give a 
close approximation of the quantity of water re- 
quired under average conditions with average 
materials. 



Mix 


Approximate Mix as 
Usually Expressed 


Water 
(Gallons 


Required 
Der Sack of 


Cement 


Volume of Aggre- 
gate after Mixing 


Cement 


Aggregate 


Cement) 


Fine 


Coarse 


Minimum 


Maximum 


1 
1 
1 
1 


5 

4H 

4 

3 


1 
1 
1 

1 


2 

2 

IM 


4 
3 
3 

23^ 


6 
5 


6M 

6 

5^^ 



This quantity will vary slightly with the quantity 
of cement and the size and grading of aggregates, 
but the table will furnish a dependable approxima- 
tion of quantities to use under average conditions. 
To get a proper strength, mixing must continue until 
all the sand is thoroughly coated with cement and 
all the stone with mortar. It takes at least a full 



MAKE AND HOW TO USE CONCRETE 105 

minute to do this after all materials, including water, 
have been placed in the drum. Even with one- 
minute mixing, aggregates will not be thoroughly 
coated with the sand-cement mortar unless the drum 
is revolved a sufficient number of times and not at 
excessive speed. Speed is regulated by the type of 
machine and the size of the batch. To insure uni- 
formity of mixes each batch must be entirely emptied 
from the drum before the next batch is put in. 
The capacity of the mixer is a factor to be considered 
on every job. This often means money to the 
contractor and should be given careful considera- 
tion. The efficiency of a mixer is considerably 
lowered if the interior blades, vanes, or other stirring 
device, are allowed to become coated with hardened 
concrete. The mixer should be carefully cleaned 
and washed each time when leaving off work. Even 
with these precautions some hardened concrete mil 
collect in the drum and it should be removed at 
frequent and regular intervals. 

STRIKING OFF AND FINISHING THE CONCRETE 
SURFACE 

Concrete pavements are finished to the required 
crown or contour by striking off the surface of the 
freshly deposited concrete with a template or strike- 
board cut to the desired crown. The strikeboard 
consists of a plain or built-up plank from two to 
three inches thick. To lengthen its life the cut-out 
portion should be shod with a strip of steel. Con- 
venient handles should be attached to the end to 



106 THE RAN SOME BOOK — HOW TO 

l)ermit operating it back and forth across the 
pavement. Some contractors have fitted tem- 
plates of this kind with handles like plow handles. 
These make it easy for the men to operate the tem- 
plate while standing and also permit using it, if 
occasion requires, to tamp the surface. Several 
combined paving gages and striking and finishing 
machines are on the market. Each of these has its 
particular points of merit. 

ROLLER AND BELT FINISHING 

Late practice in concrete pavement finishing has 
practically done away with hand floats except for 
some touching up at joints. One of the latest 
methods of finishing is to use a light steel roller 
which was first employed in concrete pavement work 
in Macon, Georgia. This roller was originated by 
Capt. J. J. Gaillard while City Engineer of Macon. 
It has since become known commercially as the 
Macon Concrete Paving Roller. 

Those not familiar with the Macon method of 
finishing concrete pavements will be interested in 
knowing its particular advantages. For ease of 
manipulation it is necessary to use a little niore 
water in the concrete than is required for maximum 
strength. Lentil the advent of the Macon roller, the 
presence of this excess quantity of water in the 
concrete could not be readily overcome. But with 
the roller method of finishing, much of the excess 
water is removed from the concrete, while at the 
same time the concrete is considerably compacted, 



MAKE AND HOW TO USE CONCRETE 107 

which insures a marked increase in strength. It is 
very necessary that the excess water be removed as 
soon as possible after concrete has been placed. 
Laboratory tests on full thickness slabs, the results 
of which were reported in the 1917 Proceedings of 
the American Society for Testing Materials, show 
that rolled slabs are twenty per cent stronger than 
those finished by the ordinary hand-floating method 
alone. The facility with which the roller may be 
used is within the range of unskilled workmen and 
has resulted in practically every contractor who has 
tried it becoming loud in its praise. The standard 
roller, ten inches in diameter and six feet long, 
weighs approximately one pound per linear foot. 
These rollers are manufactured by the Ransome- 
Leach Company. Considerable experience has re- 
sulted in formulating the following directions for use 
of the roller in concrete pavement finishing. 

. After the concrete has been struck with a template 
the roller is to be used just as soon as may be without 
displacing the concrete. In warm weather, especially 
with rock aggregate if the concrete has not been 
mixed too wet, the roller may be used immediately. 
In gravel concrete it may be necessary to wait for ten 
or fifteen minutes. In cool weather it may be neces- 
sary to delay the first use of the roller for thirty to 
forty minutes. 

If the pavement is not over twenty feet wide the 
roller may be operated from one side of the road to 
the other by a long handle. If the pavement is much 
wider than twenty feet it will be found more con- 



108 THE RAN SOME BOOK — HOW TO 

venient to attach a rope to the roller and pull it from 
one side of the pavement to the other, discarding the 
handle entirely. In this way it is possible to roll 
with the greatest facility any width pavement. The 
roller is always to be moved transversely across the 
road at a small angle so that it will move lengthwise 
of the road about two feet each trip across. 

After the first rolling the same area should be 
gone over again in about fifteen or twenty minutes. 
The concrete should receive successive rollings at 
intervals of fifteen or twenty minutes, until little or 
no free water is squeezed from the surface. This 
usually requires not less than three rollings and 
frequently four or five, depending upon the amount 
of water with which concrete has been mixed and also 
on the temperature. The less the amount of water 
and the warmer the weather, the fewer the number 
of rollings required. 

If integral curbs are being built, the water removed 
by the roller will find its way to the gutter line, and 
if not brushed off onto the subgrade will greatly 
hinder the curb work, as the water contains more or 
less laitance, which will form a deposit along the 
gutter. The best method of removing this water is 
to use an ordinary street broom, brushing the water 
along the gutter and onto the subgrade. 

BELT FINISHING 

After the roller has been run over the surface a 
proper number of times, depending upon the con- 
sistency of the concrete and the amount of water 



MAKE AND HOW TO USE CONCRETE 109 

necessary to remove it, final finishing is done with a 
belt. This may be either canvas or rubber, eight to 
twelve inches wide. It is operated by seesawing 
back and forth across the concrete surface. For the 
first belting the stroke should be at least eighteen 
inches and the forward movement should be very 
slight. At the time of the first belting the concrete 
is plastic and the long stroke moves the material 
from the high into the low spots, thus securing a 
crown that is a true arc of a circle. For subsequent 
beltings the strokes should be short, with the forward 
movement greater than that used the first time. 
Usually two beltings are given. This will produce a 
s\u"face that is as near perfect as is possible to get. 
The belt method secures a uniformity of surface and 
one free from minor irregularities that cannot be 
obtained by hand-floating methods. It produces 
an ideal finish for concrete pavement, that is, the 
even but gritty texture which makes the nonskid 
surface characteristic of concrete. 

REINFORCEMENT 

Common practice has been to omit reinforcing in 
concrete pavements less than twenty feet wide. 
Recent practice tends toward specifying reinforce- 
ment regardless of width, although it has been com- 
mon practice always to specify it for pavements 
twenty feet and wider. The practice of reinforcing 
concrete pavements has several features to commend 
it. It has the merit of preventing cracks from 
opening, thus eliminating much maintenance and 



no THE RANSOME ROOK —^ HOW TO 

keeping water from seeping through to the subgrade. 
As a rule pavements are reinforced by some type of 
mesh fabric manufactured particularly for this pur- 
pose. It is particularly necessary that slabs which 
span possibly unstable fills or cross low spots be 
reinforced. In order to get reinforcing in its proper 
position concrete has to be placed in two courses. 
This does not necessarily mean that so-called two- 
course construction be adopted. 

PROTECTION OF FINISHED PAVEMENTS 

Curing the concrete pavements has much to do 
with the results that they will give in service. Rapid 
drying out of the concrete results in a chalky surface 
and possibly surface checks or cracks. Keeping 
concrete properly wetted after initial hardening has 
taken place will not only assist in further hardening 
but will greatly increase the strength of concrete. A 
chalky surface will wear rapidly and will dust. Just 
as soon as the concrete is hard enough to stand it, 
water should be applied by spraying. If the weather 
is favorable to rapid evaporation, additional precau- 
tions must be taken to prevent the concrete from 
drying out rapidly. A canvas covering must be 
spread over the green concrete until it is hard 
enough to be sprinkled and to receive a covering of 
moist earth. An earth covering is an economical 
means of retaining moisture and protecting the con- 
crete while hardening. Water sprinkled on the 
concrete surface will run off or evaporate quickly 
and will not fully answer the purpose. If the surface 



MAKE AND HOW TO USE CONCRETE 111 

is entirely covered with two inches or more of earth 
less sprinkling will be required, but nevertheless the 
earth must be kept constantly moist for at least ten 
days. Under the most favorable conditions for 
hardening in hot weather, the pavement should be 
closed to traffic for at least fourteen days and in cold 
weather for an additional time, possibly a month or 
even more. Wliere possible to do so, an efficient 
method of curing is the ponding method. This is 
done by building earth dikes along the edges of the 
concrete and over the joints, then flooding the space 
with water to a depth of at least two inches on the 
crown. This method does not necessitate the 
handling of so much earth and insures more uniform 
curing than can be obtained by any other method. 

TEMPERATURE BELOW 65°F. DURING DAY 
BUT NO FROST AT NIGHT 

During the fall or spring when damp, cool, or rainy 
weather prevails, when the maximum temperature 
is below 65°F. and there is no danger of frost at 
night, the concrete will cure and harden more rapidly 
if left unprotected. Therefore it is advisable under 
these conditions not to cure according to the above 
methods, but to allow the concrete to get the benefit 
of the sun during the day. This does not mean that 
the concrete must be allowed to dry out. To prevent 
the moisture from evaporating too rapidly the surface 
must be sprinkled when the temperature is around 
60°F. during the middle of the day, for the number 
of days required for curing in the specifications. 



112 THE RAN SOME BOOK — HOW TO 

Later in the fall or early in the spring no sprinkling 
will be required. The concrete must be watched, 
however, and any sign of dry spots is an indication 
that sprinkling is necessary. 



TEMPERATURE BELOW 65°F. DURING DAY 
AND FROST AT NIGHT 

When there is danger of frost or a light freeze at 
night, although the day temperature be high, the 
concrete one and two days old must be sprinkled. 
That day's work must be covered with canvas, which 
must not be allowed to touch the concrete. It should 
be laid over frames and the sides reach the ground. 
The following day the canvas should be removed to 
again give the concrete the benefit of the sun. If it 
is necessary the following night to cover the previous 
day's concrete again to protect it from freezing, use 
not less than three inches of straw, marsh hay, or 
similar material, properly held down to prevent 
being blown away. 



OPENING ROAD TO TRAFFIC 

The hardening of concrete is a chemical and 
physical action requiring heat and moisture. During 
cool weather it hardens slowly and consequently 
requires a longer time to get the proper strength to 
bear traffic without injury. Therefore a longer time 
than fourteen days must elapse V)efore traffic is 



MAKE AND HOW TO USE CONCRETE 113 

permitted. Even twenty-eight days is sometimes 
not enough. 

All road contractors know the difficulty of keeping 
traffic off a new road. It is cheaper to erect sub- 
stantial barriers or to have a watchman constantly 
on guard than to remove concrete damaged by 
traffic. Detour signs with specific directions will 
always tend to restrain impatient travelers who may 
be disposed to break down barriers. 

Arrangements should be made to get the weather 
forecasts every day so as to know what to expect the 
following twenty-four hours. The forecast is usually 
posted in the post office. 

Concrete road construction is an expensive opera- 
tion in freezing weather. The thin slabs and the area 
to be protected soon eats up profits. When the 
weather reports indicate that the temperature will 
remain cool during the day and a hard freeze is likely 
at night, work should be stopped. Only when a 
short stretch is to be completed to finish a contract 
should it be continued. It will then be cheaper to 
go to the extra expense of proper precautions than to 
find it necessary later to remove defective concrete. 

Water and aggregates must be heated to insure 
proper temperature when deposited. The daj^'s work 
must be covered with at least three inches of straw, 
or similar material, and this covered with canvas 
weighted down so that the wind will not get under it. 
Work should not continue after 3.30 in the afternoon, 
and over the afternoon's concrete roofing paper 
should be placed prior to placing straw and canvas as 



114 THE RAN SOME BOOK — HOW TO 

mentioned for the morning's work. If the tempera- 
ture is cold enough the next day the canvas may be 
removed and the straw entirely covered with three 
inches of earth. This covering may be removed after 
ten days if the weather proves favorable. 

If practicable the straw may be omitted and steam 
turned under the canvas. The night watchman can 
keep the steam going in the mixer boiler for this pur- 
pose, or salamanders can be placed under the canvas. 
The next day, if weather permits, the canvas can be 
used to cover up the new work and that laid the day 
before can be covered with straw or earth. 



ESTIMATING FOR THE CONTRACTOR 
GENERAL 

For accurate work every one should compile his 
own estimating data. Figures that have been com- 
piled by others may be of some value in estimating 
the cost of a particular piece of concrete work, but 
it is almost always true that there are some details 
lacking that make the figures of some one else mis- 
leading or insufficient. They usually fail to give an 
idea of all conditions associated with the work, so a 
contractor who accepts the figures of some one else 
as the basis of an estimate is likely to find that after 
receiving a contract some of his figures represent a 
price below cost. Every contractor should keep 
data tables of his own with details of the job, which 
will help to an accurate comparison with other 
similar jobs, Contractors are frequently asked to 



MAKE AND HOW TO USE CONCRETE 115 

give an approximate estimate of the cost of a certain 
piece of work. This is quite different from an 
estimate which calls for exact details. Buildings of 
a certain class average in cost a certain price per 
cubic foot of volume. Knowing this, approximate 
figures can be given that will furnish a fair idea of 
what a finished structure will cost. 

Most important among the items that influence 
the cost of any piece of work are materials, labor, 
location of the work, transportation conditions, 
weather, character of the work, rapidity of construc- 
tion, equipment required, incidentals, and finances. 



MATERIALS 

Materials used in concrete work will be in general 
from twenty to seventy per cent of the work's total 
cost. Forming such a large item, errors in estimating 
have considerable effect on probable profit. If 
materials are not up to standard in quality, strength, 
and durability, all the work will be affected adversely 
and the contractor may be compelled to remove and 
rebuild a portion of it, thus involving a loss greater 
than his figured profit. These conditions have often 
been responsible for the financial ruin of a contractor. 

On concrete work the contractor is the manu- 
facturer. On work v/here steel and wood figure 
largely, finished material is supphed to the job and 
the contractor is merely a builder. In the case of 
concrete construction he must know the materials 
he is to use and how to combine them for best results. 



116 THE RAN SOME BOOK — HOW TO 

He is both a manufacturer and a builder. He must 
know the suitabiUty of aggregates, must know the 
principles of good concrete practice, and must see 
that good materials and good practice are used; 
otherwise he cannot guarantee the finished work. 
Often an owner, engineer, or architect compels a 
contractor to use a material or method which is not 
perhaps in favor from the standpoint of specifications, 
yet the contractor may be held responsible for the 
resulting work. The contractor should safeguard 
himself against such happenings by seeing that the 
specifications after which he is working properly 
reheve him from responsibility when compelled to 
follow variations from what is in general recognized 
as better practice. 

The item of waste must be considered in esti- 
mating. Certain quantities of cement and aggregate 
will be wasted in spite of the best handUng. 
Economy of use and care in handling will reduce 
waste to a minimum. Labor varies in cost within 
wide range; just at present it is particularly variable. 
Constant supervision must be exercised to keep 
working forces efficient. Labor cost can be esti- 
mated accurately only by knowing from long experi- 
ence the amount of work which certain classes of 
laborers can be depended upon to perform within a 
given time and under various conditions. Each job 
is a problem in itself from the labor standpoint. 
The available supply of men, whether they live near 
or far from the work, the possibility of labor 
disturbances, all must be discounted in advance. 



MAKE AND HOW TO USE CONCRETE 117 

LOCATION 

Progress of the work, time of completion, and cost 
are influenced by the location of the work with 
respect to supplies of materials and labor. If the 
work is in a locality where all labor needed can be 
obtained readily, there will be one labor situation to 
figure upon. If labor must be imported, then the 
supply is likely to be variable and more costly. 

TRANSPORTATION 

Distance from base of supplies and the condition 
of roads and availability of teams or motor trucks 
must be taken into consideration. With good roads 
there is probably no question but that motor trans- 
portation is most dependable. If large quantities of 
materials are required, speed of construction is 
Hmited by transportation facilities. Unless materials 
can be delivered and stored on the site in large 
quantities before work commences, then deliveries 
must be carefully planned so that there will be an 
uninterrupted supply to keep men and equipment 
always busy. 

A team or motor truck can be depended upon to 
haul a certain tonnage a given distance per hour on 
a certain kind of road over certain grades. The net 
results will vary in accordance with variation of 
average conditions. If roads that are good in fair 
weather quickly become bad in bad weather, 
transportation costs will rise rapidly; in fact, the 
work may have to be suspended because materials 
cannot be moved. 



118 THE RAN SOME BOOK — HOW TO 

WEATHER CONDITIONS 

Weather conditions play an important part in the 
cost of construction. Storms are often more pro- 
longed than expected, especially where the job is one 
extending over a long period of time, and the average 
conditions considered when estimating may turn out 
quite contrary to what will be actually experienced 
during the work. 



CHARACTER OF WORK 

In reinforced concrete construction cost of 
materials is secondary to labor. On mass concrete 
work, such as foundations, conditions are reversed. 
Certain kinds of work require complicated and costly 
form work. In other cases forms are relatively 
cheap. Variations in methods of placing concrete 
involve greater or less cost. Labor-saving devices 
can often be economically adopted, but experience 
is necessary to enable decision as to whether or not 
more machinery or devices on the job will pay. 

RAPIDITY OF CONSTRUCTION 

There is a limit to the speed with which concrete 
work can be carried on. Speed is considerably 
limited in cold weather. If work is speeded too much 
at any time the structure may collapse. Such con- 
ditions often compel a larger investment in forms or 
form material where otherwise it might be possible 
to make more frequent use of fewer sets of forms. 

Machine mixing is always preferable. An ap- 



MAKE AND HOW TO USE CONCRETE 119 

proved durable type of batch mixer is an indispens- 
able part of every concrete contracting equipment. 

Forms should be considered as part of the equip- 
ment. After it is known how long service forms 
or form lumber will give, the amount of form cost 
to charge to any particular job can readily be 
determined. 

All equipment must be kept in serviceable condi- 
tion. In spite of best care, however, there is constant 
depreciation, and eventually equipment must be 
replaced. Several methods are used for charging off 
the cost of equipment and setting aside a certain 
sum weekly or monthly for replacement. Most 
contractors agree that if 0.17 per cent of the total 
cost of equipment is charged to each day's work, 
sufficient funds will be accumulated to cover 
maintenance and replacement. 

It costs money to move equipment about the job 
or from one job to another. Cost of erecting and 
dismanthng the plant must also be determined and 
included in the estimate. 

EMPLOYERS' LIABILITY 

In some States the laws hold employers liable for 
accidents incurred by their employees. Liability 
insurance should be carried for the contractor's 
protection in this way. Its cost varies for different 
classes of work, but should be determined, so that 
the proper charge can be made for it in estimates. 

Contractors often have to accept as payments 
various kinds of commercial paper, such as bonds, 



120 THE RAN SOME BOOK — HOW TO 

warrants, notes, etc., instead of cash; FrequentlyX | 
such securities have a variable market value. An ^ 
understanding should be reached before bidding as 
to how payments are to be made, and if securities 
instead of currency are to be accepted the con- 
tractor should make arrangements for disposing of 
them as necessary. A contractor might estimate a 
job at S5,000, including a profit of $500. If compelled 
to take bonds that can be sold for only 90 cents on 
the dollar he therefore would receive only $4,500 
actual cash, so would have no profit. 

He should know exactly what capital he needs to 
finance the job with respect to the credit he can 
secure on materials, equipment, or other supplies, 
and time payments for purchases, so that he will at 
no time use up, even temporarily, his working 
capital. 

ESTIMATING 

Cement can be estimated accurately, therefore it 
is not necessary to increase the quantity estimated 
for. There should, however, be added something to 
the actual cost per barrel to cover the handling of 
sacks. The percentage of sacks lost is largely de- 
pendent upon how they are handled on the job. It 
is safe to say that the average loss amounts to about 
10 cents per barrel in sacks, labor of handling them, 
and accounting for them. This includes return 
freight, etc. 

AGGREGATES 

Aggregates are sold by weight or by the cubic 
yard. A unit weight is adopted and orders received 



MAKE AND HOW TO USE CONCRETE 121 

in cubic yards are converted into equivalent weight. 
The unit weight is often adopted by agreement, so 
the volume may be only approximately correct. If 
aggregates are hauled a considerable distance and 
transferred from railroad cars to wagons there will 
be some loss in weight and some actual loss on the 
job because of materials getting mixed with or 
tramped into the dirt. Losses can generally be 
figured as not to exceed ten per cent for each class of 
aggregate. 

WATER 

Often contractors fail to include cost of water in 
estimating. Sometimes it costs comparatively noth- 
ing, but frequently its cost is considerable. Quantity 
of water required can be figured at from 40 to 50 
gallons per cubic yard for concrete only. In addition, 
however, water required for operating ixdxers, 
engines, wetting forms, sprinkling concrete, sprink- 
ling subgrade in pavement work, etc., will increase 
the quantity required to 100 gallons per cubic yard. 
For mass concrete 60 to 75 gallons per cubic yard is 
a safe estimate. For slab floors, sidewalks, pave- 
ments, from 125 to 165 gallons per cubic ^''ard may 
be required, depending upon the season of the year. 
Water may have to be hauled or piped a considerable 
distance. Often water can be contracted for from 
city water mains. In such case, charges are fre- 
cjuentl}^ based on a rate of from } 2 to 13^2 cents per 
square yard of concrete pavement. 



122 THE RAN SOME BOOK — HOW TO 

FORMS 

As mentioned elsewhere, forms may cost to erect 
from $15 to $35 per thousand feet board measure of 
lumber used. The contractor should keep accurate 
cost of forms for many classes of jobs, so that event- 
ually approximate cost can be determined for any 
job. 

REINFORCING STEEL 

At present steel is much more expensive than ever 
before. Estimates should be increased ten per cent 
over actual requirements, to cover wastage from 
cutting, shaping, etc. Cost of steel is generally 
figured in place, and this cost is made up of the 
actual cost of the material plus hauling, loading, 
bending, where necessary, placing, etc. 

HAULING CHARGES 

Hauling charges include cost of loading and 
unloading, both working and waiting time of team 
and driver, and team time in travel. The less lost 
motion there is, by just so much can hauling charges 
be reduced. Rate of team travel is based usually 
on from twenty to twenty-two miles actual distance 
in ten hours on average roads and grades with 
occasional bad spots. If there are difficult places 
en route two or more teams should be run together 
so that one can be used as a ''snatch" team if the 
other gets stalled. 

A laborer will load loose material by shoveling 
from ground of car into a wagon about as follows : 



MAKE AND HOW TO USE CONCRETE 



123 



I Inexperienced 
Good Working Workmen and 
Conditions and [ Delays. Con- 
without Delays | serv^ative Esti- 

] mating 



Materials Shoveled, Working CoDtinuously 

From car to wagons — Crushed Stone . . . 

From car to wagons • — Gravel 

From car to wagons — Sand 

From ground to wagons — Plowed Clay, some 

Chunks and Stones 

From ground to wagons — Plowed Loam 
From ground to wagons — Crushed Stone . 
From ground to wagons — Sand 



Cu. Yd. 
per hr. 



Tons Cu. Yd. Tons 
per hr. per hr. per hr. 



2.2 
2.7 
3.5 



3.0 
4.0 



3.3 
4.0 
5.0 



2.0 
2.0 
2.5 



2.5 


1.5 


3.0 


2.0 


4.5 


2.0 


6.0 


3.0 



3.0 
3.0 
3.75 

1.9 
2.5 
3.0 
4.5 



A team will haul about two cubic yards on a good 
road, and about half that amount over excavated or 
soft ground. Sometimes it is necessary to use a 
^^ snatch" team to haul material economically under 
some conditions. 

A yard of material can be loaded by shovel gangs 
in about six minutes. As team time runs high it is 
often profitable to employ a loading device or extra 
wagons which can be run in place by a ^^ snatch" 
team or laboring gang. 

The following is based on six-minute loading time 
and volume loaded of 1 yard: 
Slat wagons : 

1. Load and dump (1 cubic yard), eight minutes. 

2. Hitch, dump, and unhitch (1 cubic yard), four 
minutes. 

Contractor's dump wagon: 

1. Load and dump (1 cubic yard), six minutes. 

2. Hitch, dump, and unhitch (1 cubic yard), two 
minutes. 



124 



THE RAN SOME BOOK — HOW TO 



A team will haul on 


Pounds 


Aggregate 
cu. yds. 


Sacks 
Cement 


Excavation 
cu. yds. 


Very poor earth road 

Poor earth road 

Good hard road 

Good macadam or paved road 


2,000 
2,500 
4,000 
6,000 


0.67 
0.835 
1.33 
2.00 


20 
25 
40 
60 


.8 
1.0 
1.6 
2.4 



2,000 feet of travel will take ten minutes, giving a 
haul length of 1,000 feet. For each 1,000 additional 
feet of loaded haul ten minutes should be added to 
time en route. 



HAULING CEMENT 

A team will haul loads itemized in the foregoing 
table at ten minutes per 1,000 feet of loaded 
haul. 

Loading near stock pile takes about three quarters 
of a minute of labor per sack of cement or three 
minutes per barrel. Unloading under similar condi- 
tions takes the same amount of time. The time 
which a team is delayed while doing this is dependent 
on the number of laborers employed. It may there- 
fore be profitable to have additional wagons at one 
or both ends of the haul, so that the teams will not 
be delayed. Time consumed in changing wagons 
twice may be taken as five minutes. To the net 
cost of cement when handled in sacks there should be 
added a charge of ten cents per barrel to cover 
handling empty sacks, shipping them back, and the 
loss of sacks which cannot be redeemed. 



MAKE AND HOW TO USE CONCRETE 125 

SUMMARY HAULING CHARGE 

Labor time in loading : yards 

hours at $ per hour 



Loss of team time waiting or changing wagons 
minutes at $ per minute_ 



Team time consumed in unloading- 
minutes at $ per minute 



Labor time consumed in assisting unloading- 

minutes at $ per minute- 

Team time hours en route at $ 



per hour Total expense for hauling 

yards to job 

Cost per cubic yard for hauling to job 



(Superintendence and overhead to be added to 
total estimate.) 

EXCAVATING AND GRADING 

Dirt or clay when loosened will increase in volume 
from twenty to thirty-five per cent and go back in 
fill to its original volume if compacted to the same 
degree as in its natural condition. Earth will shrink 
as much as ten per cent of its original volume if when 
transferred to another location it is compacted with 
roller. 

Loosening Material 
1. With Plow: 

(a) One plow, team and driver, and one 

helper will loosen 35 cubic yards ordinary earth 

per hour. 



126 THE RAN SOME BOOK — HOW TO 

(b) One plow, team and driver, and one 
helper will loosen 15 to 20 cubic yards of dirt 
or clay road surface per hour. 

(c) A pick-pointed plow, four horses, two 
drivers, one helper will loosen 19 yards of extra 
tough surface per hour. 

2. Picks. 

(a) One man will loosen as follows per hour: 
33^ yards of average earth. 
2 yards of tough clay. 
% yard of hardpan. 

3. Moving Material. 

Scrapers limit haul "Drag" 200 feet. "Wheel'* 500 feet 

Drag 25 ft. haul, 1 scraper, 1 team and driver, 1 helper move 60 yd. per day 
Drag 50 ft. haul, 3 scraper, 3 team and driver, 1 helper move 150 yd. per day 
Drag 100 ft. haul, 3 scraper, 3 team and driver, 1 helper move 120 yd. per day 
Drag 200 ft. haul, 3 scraper, 3 team and driver, 1 helper move 105 yd. per day 
Wheel 200 ft. haul, 3 scraper, 3 team and driver, 1 helper move 120 yd. per day 
Wheel 300 ft. haul, 3 scraper, 3 team and driver, 1 helper move 100 yd. per day 
Wheel 400 ft. haul, 3 scraper, 3 team and driver, 1 helper move 80 yd. per day 
Wheel 500 ft. haul, 3 scraper, 3 team and driver, 1 helper move 65 yd. per day 

MIXING, PLACING, AND HANDLING CONCRETE 

WITH NOT LESS THAN MINIMUM NOR MORE 

THAN MAXIMUM SIZED GANGS 

1. Mixing by hand 0.2 yards per man per 
hour 

2. Stationary mixer with elevated loading 
platform, wheeling short distance to mixer, f 
cubic yard per man supplying material to 
mixer and operating mixer. 

3. Movable mixer with mechanically hoisted 



MAKE AND HOW TO USE CONCRETE 127 

loading skip, 1 to li cubic yards per hour per 
man supplying materials to mixer and operat- 
ing mixer. 

Following is shown the amount of ^' quaky" con- 
sistency concrete which has a tendency to slop over 
from wheelbarrows on level or average grades from 
mixer to place of depositing, and also includes labor 
cost of extra men necessary to place and spread or 
spade the concrete. 

25 foot haul 0.75 cubic yards per man per hour 
100 foot haul 0.50 cubic yards per man per hour 
150 foot haul 0.40 cubic yards per man per hour 
200 foot haul 0.33| cubic yards per man per hour 
225 foot haul 0.30 cubic yards per man per hour 

The above are safe estimates where the crew is 
balanced so that no portion is materially delayed. 

When the mixer can be kept close to the place 
where concrete is being deposited the only labor 
required is that to spread the concrete. One man 
can handle up to 2.5 cubic yards per hour; two men 
can generally do more than twice that done by one 
man, and four men can handle from 12 to 16 cubic 
yards per hour, depending on the nature of the work. 

When concrete must be hoisted above the level of 
the mixer the problem is simple to solve; but it is 
difficult to give any general cost data because of the 
variation in character of plants and the many 
different heights to which the concrete is raised. 
The plant, however, when once chosen remains 
constant in daily operating cost, while its output is 
dependent upon time of operation. 



128 THE RAN SOME BOOK — HOW TO 

For example : A one-horse operated winch is used 
to hoist concrete in silo work. The quantity of con- 
crete deposited each day must be the same, as the 
forms must be filled once each day. As the height of 
hoist increases, the time consumed in raising the 
bucket of concrete increases; the horse must work 
more hours to raise the same amount of concrete and 
the time of the gang is lengthened accordingly. Even 
with engine hoist the same results follow. 

When the quantity of concrete to be deposited in a 
given period is variable, the cost will vary unless the 
size of the gang is kept adjusted to working 
conditions. 

Several types of ordinary elevator hoists are 
available. Their output may be estimated by 
dividing one fourth the loaded speed in feet per 
minute into the height to which operating. There 
is also an endless chain hoist with lugs which catch 
the barrow or wheel carts, carry them to the required 
height, automatically set them off, and return the 
empties in the same manner. With this equipment 
the output may be maintained constant by adjusting 
the number of carts or barrow^s; then the cost of 
raising concrete would be the cost of operating the 
hoist together with accessories. 

Concrete is sometimes delivered by gravity spout 
or chute, but here the hoist problem is the same, 
and the spout substitutes the conveying of concrete 
by barrows or carts from the elevator to place where 
deposited. 

For general estimating the following cost of con- 



MAKE AND HOW TO USE CONCRETE 129 

Crete work complete may be used in normal times. 
These figures include forms, profit, and all other 
necessary items. 

Concrete in large masses $4 to $6 per cubic yard 
where few forms enclose a large quantity of concrete. 
For example: Engine foundations, pavement foun- 
dations, building foundations, bridge abutments, and 
walls two feet or more thick, of medium height. 

Plain concrete walls from eight to sixteen inches 
thick, and other plain concrete construction re- 
quiring simple form work and some steel reinforce- 
ment for temperature stresses, $6 to $8 per cubic 
yard. 

The same class of work, but more complicated, up 
to S12. 

Reinforced concrete work, including bridge floors, 
building construction, etc., $12 to $20, with a 
general average figure of $15. 

^Concrete sidewalks, $7 to $9 per cubic yard. 

*Concrete street pavements, $7.50 to $9.50 per 
cubic yard. 

SURFACE TREATMENT OF CONCRETE 

There being practically no limit to the variation 
possible in the treatment of concrete surfaces, 
naturally the cost must often resolve itself into the 
known items, such as materials required, scaffolding, 
and the unknown quantity of labor, which must be 



*Note: For his own information the contractor must figure the volume of 
concrete. As pavement specifications may vary in stating the thickness required, 
the contractor will then reduce his cubic-yard cost to a square-yard basis, as paving 
costs are usually expressed in this way. 



130 



THE RAN SOME BOOK — HOW TO 



conservatively estimated from the contractor's know- 
ledge of the surface area that can be treated in a 
given time by the men available. Hence the con- 
tractor must have personal knowledge of the ability 
of the men who will actually do the work or feel 
certain that he can teach men to do it for the cost 
estimated. 

The following table gives the quantities of 
materials required for Portland cement exterior 
plastering of varying thicknesses: 

NUMBER OF SQUARE FEET OF WALL SURFACE 

COVERED PER SACK OF CEMENT, FOR 

DIFFERENT PROPORTIONS AND VARYING 

THICKNESS OF PLASTERING 



Pro- 
portions 
of 


MATERIALS 


TOTAL THICKNESS OF PLASTER 


Sacks 
Cement 


Cu. Ft. 

Sand 


Bushels 
Hair* 


J^in. 


Min. 


lin. 


IK in. 


IK in. 


Mixture 


Sq. Ft. 
Covered 


Sq. Ft. 
Covered 


Sq. Ft. 
Covered 


Sq. Ft. 
Covered 


Sq. Ft. 
Covered 


1: 1 

1:2 

1:21^ 

1:3 


i 


3 


i 

H 


33.0 
42.0 
50.4 
59.4 
67.8 


22.0 
28.0 
33.6 
39.6 
45.2 


16.5 
21.0 
25.2 
29.7 
33.9 


13.2 
16.0 
20.1 
23.7 
27.1 


11.0 
14.0 
16.8 
19.8 
21.6 



*Used in scratch coat only. 

Note. These figures are based on average conditions and may vary 10 per cent 
either way, according to the quaUty of the sand used. No allowance is made for 
waste. 



After having decided upon the thickness of the 
wall plaster and the mixture to be used, it is easy to 
determine the total materials required for covering 
a given wall surface, since the table shows the number 
of square feet of surface covered by the mortar re- 



MAKE AND HOW TO USE CONCRETE 131 

suiting from one sack of cement. Waste can be 
reduced by placing a plank on the ground at the base 
of the wall to catch plaster that falls. Such plaster 
should never be used after it has once begun to 
harden, and therefore should not be allowed to 
accumulate but should be gathered up promptly 
and remixed with the mortar already prepared. 
Cement plaster should not be mixed in batches 
larger than are needed for immediate use, otherwise 
some of the mortar may begin to harden before it 
can be used and must be thrown away. 

Cement stucco work generally costs from $1.50 
to $1.75 per square yard, including building paper 
and wood or metal lath, the metal lath costing a 
little more than the wood. The two-coat smooth 
work often costs less than $1.50. When granite or 
marble chips are used in the rough exposed dry or 
other dash, the extra cost of such materials may 
raise the price to $1.75 or slightly more. 

When the form face is plastered with chips or 
colored pebbles backed by the regular wall con- 
crete, and after the forms are removed, the surface 
film of cement is brushed or washed with a weak 
solution of acid, the extra cost generally runs from 
five to ten cents per square foot of surface. 

Concrete wall surfaces are treated by one coat of 
cement mortar, smooth or dash finish, at a cost of 
approximately five cents per square foot. Concrete 
surfaces are frequently tooled to reveal the aggregate. 

The tooth-axed surface is probably the most 
widely known. This work is done by lightly chipping 



132 



THE RAN SOME BOOK — HOW TO 



with a tooth-ax and thus breaking away the surface 
skin of the concrete. The work is generally done in 
panels or to produce designs with borders or certain 
areas left smooth. The smooth surfaces are rubbed 
with cement grout and a carborundum stone and 
pointed up. The work generally is contracted for at 
from six to seven cents per square foot of exposed 
area of the building with the addition of all areas to 
be treated at angles to the surface. Stone cutters are 
preferable for this work and one man will cut from 
80 to 100 square feet per day of eight hours or over, 
approximately 150 square feet of surface in like 
time. 

BRICKWORK— WALLS 

8| in. by 2| in. by 4 in. brick -^ in. joints requires 12 cu. ft. of 
mortar per 1,000 brick. With a 1 cement 3 sand mix, 1 barrel cement 
per 1,000 brick. Allowing for waste 1.25 barrels cement per 1,000 
brick. 1,000 brick will lay 475 square jeet of 12 in. wall. 

CONCRETE FOUNDATIONS— WALLS, ETC. 



1 cu. ft. 
Concrete 


Sacks of 
Cement 


1 cu. 3'd. 
Concrete 


Bbls. of 
Cement 




1:1 

13^:3 

2:4 

23^:5 
3:6 


.5404 

.2808 
.2220 
.1848 
. 1570 


1:1:1 

1:13^:3 

1:2:4 

1:2^:5 

1:3:6 


3.375 
1.895 
1.498 
1.247 
1.060 



MAKE AND HOW TO USE CONCRETE 



133 



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134 



THE RAN SOME BOOK — HOW TO 



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MAKE AND HOW TO USE CONCRETE 



135 



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136 



THE RAN SOME BOOK — HOW TO 






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MAKE AND HOW TO USE CONCRETE 



137 



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138 



THE RAN SOME BOOK — HOW TO 



QUANTITIES OF PORTLAND CEMENT, SAND, AND 

PEBBLES OR CRUSHED STONE FOR 100 SQUARE 

FEET OF CONCRETE 10 INCHES THICK, 

EQUAL TO 3.08 CUBIC YARDS 



Proportions 


Quantities 


Sacks 


Cu. Ft. Cu. Ft. 


Sacks 


Cu. Yd. 


Cu. Yd. 


of 


of Pebbles 


of 


of 


Pebbles 


Cement 


Sand or Stone 


Cement 


Sand 


or Stone 




1 
1 


60.2 


2.23 






13^2 




47.7 


2.65 






2 




39.4 


2.92 






2y2 




33.8 


3.13 






3 




29.5 


3.29 






1 


1 


41.7 


1.54 


1.54 




13^ 3 


23.4 


1.30 


2.60 




2 


3 


21.5 


1.59 


2.38 


I 


2 


4 


18.5 


1.37 


2.74 




2K 


4 


17.2 


1.59 


2.54 




23^ 


o 


15.4 


1.43 


2.86 




3 


o 


14.2 


1.58 


2.64 



Note. These quantities can be safely used for estimating, 
ordering materials, and, after the work is done, as a check to prove 
that the required quantity of cement has been used. Actual quantity 
of materials u.sed in the concrete should not vary more than ten per 
cent above or below the quantities given in the table. 

This table can readily be used for any concrete 
structures which can be measured in area and which 
are of uniform thickness over any considerable area, 
such as walls, floors, and walks. 

The following examples illustrate the use of the 
table : 

Example 1. Required the quantity of materials for a 12 inch 
thick basement wall, 6 feet 5 inches high above footing, for a house 
25 feet by 40 feet outside dimensions. The footing 1 foot 6 inches 
wide and 6 inches thick. Concrete proportioned 1:3:5. 



MAKE AND HOW TO USE CONCRETE 139 

Wall: 

Length of waU 25+25+39+39 = 128 ft. 

Height of wall 6 ft. 5 in. =6x^2 =6.417 ft. 

Area of wall = 128X6.417 =82^1.4 sq. ft. 

Thickness of wall = 12 in. 

Quantities of materials for wall concrete: 

Factor for multiplying units in 

table = 821.4 12 

X — =8.214X1.2=9.8568; 

100 10 

Take 9.86 

Sacks of cement = 14.2 X9.86 = 140.0 

Cu. yd. of sand = 1.58X9.86 = 15.6 

Cu. yd. of pebbles or crushed stone = 2.64X9.86 =26.0 

Footing : 

Length of footing = 25.5+25.5+37.5+37.5 = 126 ft. 

Width of footing = 1 ft. 6 in.=lx% = 1.5 ft. 

Area of footing = 126 X 1 .5 = 189 ft. 

Thickness of footing =6 in. 

Quantities of materials for footing : 

Factor for multiplying units in the 

table =189 6 

X — = 1.89X.6 = 1.134 = 1.13 

100 10 

Sacks of cement = 14.2X1.13 = 16.0 

Cu. yd. of sand =1.58X1.13 = 1.8 

Cu. yd. of pebbles or stone = 2.64X1.13 =3.0 

Total quantities of materials: 

Sacks of cement = 140+16 = 156.0 

Cu. yd. of sand =15.6+1.8 = 17.4 or 17.5 

Cu. yd. of pebbles =26.0+3 =29.0 

Example 2. Required the quantities for a concrete floor for a 
basement. Interior dimensions of the basement 23 feet by 38 feet. 
Floor 5 inches thick over all, with 4 inch base of concrete propor- 
tioned 1:23^:5, and 1 inch wearing course composed of cement 
mortar proportioned 1:2. 

Area of floor = 23 X 38 = 874 sq . f t . 

Factor for multiplying quantities in table for 

base =874 4 

— X -=8.74X.4=3.5 
100 10 



140 



THE RAN SOME BOOK — HOW TO 



Quantities of materials for base concrete : 
Sacks of cement = 15.4X3.5 =54.0 
Cu. yd. of sand =1.43X3.5=5.0 
Cu. yd. of pebbles or stone =2.86X3.5 = 10.0 
Factor for multiplying quantities in table for 



wearing surface = 



= 874 1 

X— =8.74X.1=.9 

100 10 



Quantities of materials for wearing surface mortar: 
Sacks of cement =39.4 X. 9 =35.5 
Cu. yd. of sand =2.92 X. 9 =2.6 cu. yd. 

Total quantities of materials for floor : 
Sacks of cement = 54.0+35.4 =89.5 
Cu. yd. of sand =5.0+2.6 = 7.6 or 7.5 
Cu. yd. of pebbles or stone = 10.0 



SURFACE AREA (IN SQUARE FEET) OF CONCRETE 

SLABS OR WALLS OF VARIOUS THICKNESSES 

AND PROPORTIONS THAT CAN BE MADE 

WITH ONE SACK OF CEMENT 



Thickness 




Concrete Mixture 




of Slab 








or Wall 






1 




in inches 


1:2:3 


1:2:4 


1:2^:4 | 1:2^:5 


1:3:5 


3 


15.52 


17.88 


19.42 1 21.77 


23.2 


33^ 


13.31 


15.33 


16.65 18.67 


19.9 


4 


11.64 


13.41 


14.56 16.33 


17.4 


43^ 


10.36 


11.93 


12.96 


14.53 


15.5 


5 


9.31 


10.73 


11.65 


13.06 


13.9 


5^ 


8.46 


9.74 


10.58 


11.86 


12.6 


6 


7.76 


8.94 


9.71 


10.88 


11.6 


63^ 


7.18 


8.27 


8.98 


10.07 


10.7 


7 


6.65 


7.66 


8.33 


9.33 


9.9 


8 


5.82 


6.70 


7.28 1 8.16 


8.7 


10 


4.66 


5.36 


5.83 i 6.53 


6.9 


12 


3.88 


4.47 


4.85 5.44 


5.8 


14 


3.32 


3.83 


4.16 4.66 


4.7 


16 


2.91 


3.35 


3.64 4.08 


4.3 



MAKE AND HOW TO USE CONCRETE 141 

WEIGHTS AND VOLUMES 

Portland cement weighs per barrel, net 376 lb. 

Portland cement weighs per bag, net 94 lb. 

Natural cement weighs per barrel, net 282 lb. 

Natural cement weighs per bag, net 94 lb. 

Loose Portland cement averages per cubic foot about 92 lb. 
Weight of paste of neat Portland cement averages per 

cubic foot about 137 lb. 

Volume of paste made from 100 lb. of neat Portland 

cement averages about 0.86 cu. ft. 

Weight of Portland cement mortar in proportions 

1: 23^ averages per cubic foot 135 1b. 

Weight of Portland cement concrete averages per cubic 

foot about 130 lb. 

Cinder concrete averages 112 lb. 

Conglomerate concrete averages 150 lb. 

Gravel concrete averages 150 lb. 

Limestone concrete averages 148 lb. 

Sandstone concrete averages 143 lb. 

Trap concrete averages 155 lb. 



I 



MAKE AND HOW TO USE CONCRETE 143 




4" 



RANSOME BANTAM MIXER 

The Ransome Bantam Mixer is of the low charging type 
and is regularly equipped with platform and runways. 
The drum has a capacity of 10 cu. ft. of loose material and 
will produce approximately 6 cu. yd. of concrete per hour. 
A gasoline engine of 3 H.P. is furnished, amply protected 
from the weather by a steel roof and side curtains. 



WRITE FOR RANSOME BANTAM BOOKLET 



144 



THE RAN SOME BOOK — HOW TO 




RANSOME BANTAM SENIOR 

The Ransome Bantam Senior Mixer is built along the 
same general lines as the Bantam, except that it is regularly 
furnished with a side loader, automatic water tank, and 
4 H.P. gasoline engine. The output is therefore increased 
to 73^ cu. yds. of concrete per hour. 



WRITE FOR RANSOME BANTAM BOOKLET 



MAKE AND HOW TO USE CONCRETE 145 




RANSOME BANTAM JUNIOR 

FARMERS' TYPE 

The Ransome Bantam Junior Mixer of the Farmers is 
furnished with 2}/^ H.P. gasoUne engine on a separate 
frame and trucks, so that the engine may be used for 
miscellaneous purposes about the farm or estate. The 
Contractors' Type of this machine has the engine mounted 
on mixer frame. Capacity of this mixer is 5 cu. ft. loose 
material per batch or 3 cu. yd. of concrete per hour. 



WRITE FOR RANSOME BANTAM BOOKLET 



146 



THE RAN SOME BOOK --HOW TO 




RANSOME BANTAM PAVER 

The Ransome Bantam Paver is of the end load, end dis- 
charge type, having a capacity of 10 cu. ft. loose material 
per batch. It is equipped with open-end pivot hopper, 
10 ft. distributing chute, and 6 H.P. gasoline engine, chain 
drive. The self-propelling traction as well as the porta- 
bihty and light weight are attractive features of this 
machine. 



WRITE FOR ''RANSOME ROADS'' BOOKLET 



MAKE AND HOW TO USE CONCRETE 147 




RANSOME STREET PAVER — MODEL 10-E 

BUCKET AND BOOM TYPE 

The Ransome Road Payee, Bucket and Boom Type, is 
a distinctly high grade machine for hea\'y^ work. It is 
equipped with a 20 ft. distributing boom, on which runs an 
automatic dumping bucket. This mixer is equipped with 
steam power and has self-propelling traction. It is made 
in one size onty, capacity 14 cu. ft. loose material per 
batch. 



WRITE FOR ''RANSOME ROADS'' BOOKLET 



148 



THE RAN SOME BOOK — HOW TO 



^r'^'S, 




RANSOME SPOUT STREET PAVER 

• The Ransome Road Paver, Spout Type, is made along 
the same lines as the Bucket and Boom Tj^pe, except that 
it is equipped with a distributing chute 15 ft. long. It is 
made in two sizes only, namely 14 and 30 cu. ft. of loose 
material per batch, with steam power. 



WRITE FOR ''RANSOME ROADS'' BOOKLET 



MAKE AND HOW TO USE CONCRETE 



149 




RANSOME MIXER WITH DIRECT-GEARED 
ENGINE 

WITH FIXED BATCH HOPPER 

The above illustration shows the Standard Type of ' 
Ransome Mixers equipped mth Fixed Batch Hopper. 
These machines are made in sizes ranging from a batch 
capacity of 10 to 80 cu. ft. of loose material. Electric, 
steam, and gasoline power is furnished as desired. 



WRITE FOR "RANSOME MIXERS'' BOOKLET 



150 THE RAN SOME BOOK — HOW TO 





RANSOME MIXER WITH COMPLETE STEAM 
PLANT 

DISCHARGE SIDE 

The above illustration shows the discharge side of the 
Ransome Mixer, Standard Type, on steel frame, with 
complete steam-power plant. These Mixers are equipped 
with cut steel gears and split adjustable bearings. Trac- 
tion rings have heavy steel bands welded and shrunk on. 



WRITE FOR "RANSOME MIXERS" BOOKLET 



MAKE AXD HOW TO USE COXCRETE 151 




RANSOME MIXER WITH ELECTRIC MOTOR 

WITH PIVOT HOPPER 

Due to simplicity in the direct connection of motors the 
above type of jMixer is very popular. The standard Ran- 
some side loader attachment is also illustrated, showing 
the cone friction hoist and oversize pivot hopper bucket. 
All motors are furnished ^\'ith steel housings. 



WRITE FOR "RANSOME MIXERS" BOOKLET 



152 



THE RAN SOME BOOK — HOW TO 




A COMPLETE barge plant is shown above, on which was 
used the following Ransome equipment: Mixer, Steel 
Tower, Hoist Bucket, Tower Bin, Spouting and Boom 
Irons. This type of spouting layout is known as a ''Boom 
Plant.'' 



WRITE FOR RANSOME SPOUTING CATALOG 



MAKE AND HOW TO USE CONCRETE 



153 



|W 




1 i 



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a 

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WRITE FOR RAN SOME SPOUTING CATALOG 



154 



THE RAN SOME BOOK — HOW TO 




1^ 



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WRITE FOR RAN SOME SPOUTING CATALOG 



MAKE AND HOW TO USE CONCRETE 155 




RANSOME-CANNIFF GROUT INJECTORS 

Ransome-Canniff Grout Injectors are designed for 
mixing and placing grout by compressed air. Cement and 
sand are delivered to the grout tank through the charging 
door, the proper proportion of water being added. The 
grout is mixed by allowing the compressed air to blow in 
at the bottom, which keeps the mixture '^boiling" and 
prevents sand and cement settling into and choking the 
outlet pipe. During this operation the blow-off valve is 
open. 

WRITE FOR RAN SOME PNEUMATIC BOOKLET 



156 



THE RAN SOME BOOK — HOW TO 




RANSOME-CANNIFF PNEUMATIC MACHINE 

The advantages of pneumatic machinery are many and 
far reaching. The mixer is located at a point where the 
aggregates can be handled most conveniently and economi- 
cally. The transportation of the mixed concrete to the 
forms is accomplished with the least possible expenditure 
of power and of material. The conveying pipe can be laid 
in almost any direction required. It takes up but little 
room — a highl}^ essential feature in tunnel and subwaj^ 
work — and needs no heavy foundation supports or pre- 
pared runways of any sort. The concrete can be elevated 
to any required height or conveyed any reasonable dis- 
tance in a minimum of time. The concrete is placed 
through a short length of rubber hose of the same inside 



WRITE FOR RAN SOME PNEUMATIC BOOKLET 



MAKE AND HOW TO USE CONCRETE 



157 




RANSOME-CANNIFF PLACER ASSEMBLY 

diameter as the pipe. No hand spreading or tamping is 
necessary, as the concrete can be directed to the exact spot 
where it is needed. All labor between the mixer and the 
forms is eliminated except the two men handling the hose. 
Not only is the work accomplished more rapidly, but 
the cost is found in most cases to be considerably under 
that for any other method. The savings effected depend, 
of course, upon the particular type of work. In tunnel and 
subway construction it has amounted to over $2.50 per 
cubic yard of concrete placed. 



WRITE FOR RAN SOME PNEUMATIC BOOKLET 



158 



THE RAN SOME BOOK — HOW TO 




RANSOME HOIST BUCKETS 

Ransome Hoist Buckets are designed for use in towers 
where the work is too high to be reached by easy wheeling. 
The bucket is constructed along the most simple lines, 
catches and trips having been eliminated. A substantial 
bail, built up of angle irons, operates between two 5^4 in. 
wooden guides, and is furnished at the lower end with 
journals, in which rests the trunnion of the bucket proper. 
By removing a front guide at any point, automatic dis- 
charge of the bucket will take place through the space so 
left. 



WRITE FOR RANSOME EQUIPMENT BOOKLET 



MAKE AND HOW TO USE CONCRETE 



159 




RANSOME CONCRETE BINS 

Ransome Concrete Bins are used in connection T\ith 
Ransome Hoist Towers, either in conjunction with. Ran- 
some Spouting or where the concrete is discharged directly 
into concrete carts. The sizes match up with the capa- 
cities of Ransome Mixers. 



WRITE FOR RANSOME EQUIPMENT BOOKLET 



160 THE RAN SOME BOOK — HOW TO 



RANSOME BIN GATES 

--^Mji^^^^ Of the three different styles 

I^BlMT of Ransome Bin Gates some 

JbB^K one will always be found suit- 

^^^I^H^^^^k able for any position on the 

^f^^^ ^^1^^^^^. aggregate storage bins. The 

Vertical Bin Gate . , ., . 

upper view shows the gate 
used for discharging stone and sand through the bottom 
of the bin; the center, gate 
for discharging through the 
bottom and delivering on one 
side or the other; and the 
lower illustration shows the 
gate for attaching to the ver- 
tical side instead of the bot- 
tom of the bin. Not only the Bottom Bm Gate 

quahty of material used in Ransome Bin Gates, but 
the care in workmanship, in- 
sures easy operation and per- 
fect closure, even under the 
severe conditions of this 
work. 

Front Bin Gate 



WRITE FOR RANSOME EQUIPMENT BOOKLET 





MAKE AND HOW TO USE CONCRETE 161 




RANSOME CONCRETE CARTS 

Ransome Concrete Carts, when used in place of wheel- 
barrows for the distribution of concrete, cut down the 
number of wheelers to about one half, sometimes to one 
third of the original force. These carts hold 6 cu. ft., 
water measure. A special Ransome feature is the reversi- 
bility of the handles. These may be quickly changed end 
for end. The round contour of the cart bodies facihtates 
quick, clean dumping. Ransome Carts are furnished mth 
or without legs. The legs are necessary for elevator work. 



Capacity 


Weight 


Diameter of Wheels 


Diameter of Axle 


6 cu. ft. 


255 lb. 


42 X 2 in. 


IMin. 



WRITE FOR RANSOME EQUIPMENT BOOKLET 



162 THE RANSOME BOOK 




RANSOME BAR CUTTERS 

Ransome Bar Cutters are made from solid steel forgings 
— no cast iron whatever being used. They may cost a 
bit more at the start, but they are by all odds the most 
economical in the end. The lightweight cutter will handle 
square and round stock up to ^ in., and flat iron 3f by 2 in. 
The heavier cutter will cut 134 in. round or square stock, 
and flat iron up to % by 33^ in. For heavier stocks a 
power cutter is advisable. 



WRITE FOR RANSOME EQUIPMENT BOOKLET 



INDEX 

PAGE 

Introduction iii 

Action of Sea Water on Concrete 58 

Aggregates 2 

Aggregates 120 

Apparatus 88 

Back Filling . 76 

Batch Mixers 28 

Belt Finishing 108 

Brickwork — Walls 132 

Care of Reinforcement before Use 44 

Causes of Dusting 62 

Character of Work 118 

COLORIMETRIC TeST FOR ORGANIC IMPURITIES IN SaND 86 

Concrete Estimating Tables and Examples .... 45 

Concrete Floors 61 

Concrete Foundations — Walls, etc 132 

Concrete — How to Make and Use it ...... 1 

Concrete Tanks 64 

Concrete Walks 63 

Concreting in Cold Weather 54 

Consistency of Mixtures 29 

Cost of Form Work 38 

Design for Washing Plant 13 

Dimensions and Materials for Roofs of Silos . . 68 

Drainage 92 

Employers' Liability 119 

Estimates on Specific Contracts 133 

Estimating 120 

Estimating for the Contractor 114 

Excavating and Grading 112 

Excavation 76 

Expanded Metal and Mesh Fabric 43 

163 



164 INDEX 

PAGE 

Field Practice in Concrete Pavement Construction 83 

Finishing Cuts and Fills 98 

Finishing Pavement Slabs at Joints 92 

Fire Resistance of Aggregates 22 

Forms 99 

Forms 122 

Forms and Footings 77 

Forms for Concrete 33 

Form Removal 40 

General 1 

Grading 92 

Grading of Aggregates 16 

Handling Excess Material 97 

Handling Materials on the Job 93 

Hauling Cement 124 

Hauling Charges 122 

Importance of Bracing Forms 39 

Joints 95 

Location ■.. 117 

Location of Reinforcement 41 

Materials 115 

Materials Required for Concrete 138 

Materials Required for Plaster 137 

Materials Used as Reinforcement 42 

Materials for Silo Footing and Floors 68 

Materials Required for Sidewalks and Floors . . 135 

Material for Walls of Monolithic Silo 70 

Measuring Materials 29 

Method for Field Test 87 

Methods of Placing 49 

Mixing Concrete 28 

Mixing Concrete 101 

Mixing, Placing, and Handling Concrete 126 

Mixing Water 23 

Mixing Water 91 

Mixtures 77 

Monolithic Silos 76 

Object of Specifications 85 

Opening Road to Traffic 112 



INDEX 165 

PAGE 

Placing Concrete 49 

Placing Concrete 96 

Placing Concrete and Steel Reinforcement ... 77 

Placing Concrete under Water 57 

Planning Forms Economically ....'.. 37 

Principles of Reinforcing 41 

Proportioning 90 

Proportioning Concrete IMixtures 24 

Protecting Finished Work 52 

Protection of Finished Pavements 110 

Quantities of Materials for Paving 94 

Quantity of Water 30 

Quantity of Water 103 

Ransome Products 142-161 

Rapidity of Construction 118 

Reinforcing Concrete 41 

Reinforcement 109 

Reinforcing Steel 122 

Requirements of Wood Forms 34 

Roller and Belt Finishing ............ 106 

Roofs 79 

Safe Load for Studs or Posts 36 

Screen Bank -Run Material 4 

Screening Pays 5 

Shoulders 98 

Silos 66 

Size of Aggregates 23 

Squ.are Feet per Sack of Cement for Wall Plastering 130 

Storage Requirements 2 

Striking off and Finishing the Concrete Surface 105 

sumaliry 88 

Summary Hauling Charge 125 

Surface Area of Concrete Slabs or Walls .... 140 

Surface Treatment of Concrete 129 

Table Giving Horizontal Reinforcement for Block 

Silos 73 

Table Giving Lineal Feet of Triangle jNIesh Rein- 
forcement 74 

Table of IMaterials Required 27 



166 INDEX 

PAGE 

Table of Materials for Roof Slabs 80 

Table of Recommended Mixtures 24 

Table of Reinforcing for Roof Slabs 81 

Table of Triangle Mesh Reinforcement 69 

Table Showing Capacity of Silos in Tons 67 

Table Showing Concrete Blocks Required ... 72 

Table Showing Method of Reinforcing Silos ... 71 

Table Showing Thickness of Roof Slabs 79 

Temperature Below 65°F. During Day but no Frost 

AT Night Ill 

Temperature Below 65°F. During Day and Frost 

AT Night 112 

Testing Coarse Aggregates 89 

Time of Mixing 32 

Transportation 117 

Types of Concrete Pavements 84 

Types of Floors 62 

Types of Forms 33 

Washing Aggregates 6 

Water 121 

Weather Conditions 118 

Weights and Volumes 141 

Wetting or Greasing Forms 38 



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